Jim Burns - Are Some Blu Ray Players Better on HDMI HD Picture Quality? [Text View]

Steve Bruzonsky

03-01-09, 09:22 AM

AND IN CONCLUSION............... Time to bring this thread to a close.. I found out what I wanted to find out with the polling... It has been a good thread and quite enlightening...

RE:$2K players and how to waste your money....

Yes.. You'd think there was some sort of paradigm shift in Blu Ray technology... The last disc paradigm shift was the move to 1080P24 from the early players only doing 1080P60. And before that, the transition from DVD to Blu Ray.

I see many $2K owners, particularly those with the latest players gushing over all its 'new' advancements in technology.. Fact is, many folks who buy a lot of players tend to like the newest, most expensive the best. It's a fact, no one likes to spend $2K and immediately say that a lower cost player offers similar performance.. So, you'll never get a true read on comparisons with someone fully invested in their $2K player.

Based on the fact, the upcoming Denon at $4K will be the new king.. For no reason other than its exorbitant price...

Personally, in being in this hobby buying gear of all price ranges over the last 20 years I have come to some conclusions...

1. In the world that was analog, there were greater improvements with generations as there was so much to do to clean up / improve analog.. Anyone remember the Faroudja VP301 at the 'lowered' price of $15K...? a piece that did the unheard of by taking 480i and upconverting it to 600P??!! A bargain price compared to the $25K / $30K flagship Faroudjas.. I remember buying my first Faroudja.. What an improvement for my LD player!!

2. I don't get a 'hard-on' to buy the latest piece just to have it.. I used to be like that when I thought spending more meant getting more.. Today in a 1080P24 / bitstream world, the player differences are just too marginal. It looks more like ignorance than anything else.

3. I've learned to by smarter and spend where it will make differences... WIth the glut of new BD players, if looking for audio and video improvements when running 1080P24 / bitstream / LPCM, it is just a waste of money.. Now if you want better build, fit and finish, etc... THen you do get rewarded for your $2K purchase.

4. Personally, I spend my money wisely on HT - not spending just to spend - if I were still that way, and I used to be, I'd have a Pioneer 09 in my stable by now. Cna I afford one? Of course... But, I know it is no better than anything else so why spend on it?

I'l give some examples of my smarter purchases?
1. ISCO III anamorphic lens at $6K it is an expensive piece of glass but coming from the far cheaper Panamorph, the acrylic block is no match for precision glass. The anamorphic lens is a most important piece in any video set up. The difference is easily discernable compared to cheaper imitators.

2. Lumagen Radiance Scaler: at $4K, it isn't out of bounds in terms of cost, but to get perfect calibrations for up to 15 sources (6 HDMI), nothing even comes close. I have 7 sources... All perfectly dialed in to my ISF calibrated projector.

3. Stewart Vistascope screen... Yes at $25K it is more than most folks whole system. But for masking all aspect ratios in a 14' wide, microperfed screen, there is nothing better. Many folks here run plasmas, but when going to scope, you've got the same black bars a $300 LCD has - it distracts and kills perceived contrast. The 09 / 3800 cannot help this either. Better to spend those 09 dollars towards front projection.. The Vistascope also excels particularly with the new masks that are truly transparent to audio (like speaker cloth)..

*Notice, I didn't list my Denon 3800. I have the new OPPO and at 1080P24, I can't see a difference at a fraction of the cost. Nor with lossless over HDMI.

So, why should I not spend a measly $2K on a Pioneer 09??? Simple. There has been no paradigm shift in technology - so it would be an utter waste of money. A complete waste of money compared to what is available today (and it can't decode DTS MA). The smart money is to stay away from the Denon 3800, Pioneer 09, Sony ES if 24P is your primary reason to buy for 24P improvement / or lossless improvement... Yes, there is a feeding frenzy in a couple $2K threads and it is easy to get sucked in, but the improvements are simply delusions of grandeur. Everytime I read, 'you gotta try it yourself' or 'how come it is the owners who all glow about it', I laugh... I used to be that way with new stuff. It's fun to buy and declare your newest piece the holy grail of its catagory. But with Blu Ray today, the 'improvements' @24P and digital lossless are pure nonsense. There are no new shifts in technology.

Those who know, know better.

Now here's someone who is asking this question and answering it for himself from an observational basis using a Qualia004 soon to be replaced by an even better projector.

http://www.avsforum.com/avs-vb/showthread.php?t=1122617&page=28

He doesn't think there's any difference in HDMI 1080p24 picture quality among some Blu Ray playes he's used in his system and he doesn't have to be funny to say it. HA!

Steve Bruzonsky

03-01-09, 09:27 AM

You don't need us for comic relief you are right ,your posts are doing very well on their own. I hope you are doing it intentionally,you are right ?

Art

Go ahead. Make my day!!!@@@

Intentionally? When have I ever done anything like that?:mad::D

I'm surprised you Adam Sandler types havan't tried a Chu Gai on me like
"Get a cheap Blu Ray player AND add a Hooker and the visuals will instantly improve." (woops, I would have thought that Chu Gai would be the one to come up with the Hooker furniture thingamagic, but it was actually Alan Gouger. Nice to know I can start a thread on the same thing but disguise it as a real video thread so AVS won't delete it as they would if anyone other than Alan started a Hooker thread. HAAAA!!!:D:eek:

Steve Bruzonsky

03-01-09, 09:28 AM

What are the odds that the real Jim Burns will come on this thread now and tell us his true observations in answer to the original question????

Art Sonneborn

03-01-09, 09:51 AM

What are the odds that the real Jim Burns will come on this thread now and tell us his true observations in answer to the original question????

Well I hope if he does that he sees the the question is rediculous.

Art

goneten

03-01-09, 09:57 AM

Well I hope if he does that he sees the the question is rediculous.

+1 !

Regards,

Alan Gouger

03-01-09, 10:15 AM

Now here's someone who is asking this question and answering it for himself from an observational basis using a Qualia004 soon to be replaced by an even better projector.

http://www.avsforum.com/avs-vb/showthread.php?t=1122617&page=28

He doesn't think there's any difference in HDMI 1080p24 picture quality among some Blu Ray playes he's used in his system and he doesn't have to be funny to say it. HA!

Ill bite.

I also do not see any real visual PQ difference between players regardless of cost via HDMI " But"
there are some reasons to be concerned or at least I have been told. Depending on how HDCP is handled in the video path it can have an effect on PQ. You also do not know what players are giving us true 1080p24 direct right off the disc, only the manufacture would know for sure. What about the players that have video processing features such as brightness, gamma, sharpness etc. The signal from those players are definitely going through an additional pre processing stage before it leaves the player. While you may set the sharpness to 0
the manufacture may want you to see a sharper image so 0 in the outside might actually be +1 inside, again you never know. For these players it would be nice to have a "byPass" selection in the set up menu.
I own an HD SDI player for one reason it does ensure I am getting the information right off the disc exiting the player via the shortest video path.

.

Steve Bruzonsky

03-01-09, 10:25 AM

Well I hope if he does that he sees the the question is rediculous.

Art

Art, do you still think "the question is rediculous" in view of Alan Gouger's
informed answer?????

Steve Bruzonsky

03-01-09, 10:26 AM

FrantzM

03-01-09, 10:35 AM

Hi

I think the question is valid and I for one take it seriously. I am aptiently building my understanding of high end video and as in many hobbies that involve perception, one learn to "see"... I thought my now-to-be-replaced Sony Ruby untouchable but I have learned to see more in a picture.. and now can see it surpassed by several less expensive projectors and thoroughly trashed by others... I did buy early in the High Definition disc and have both HDVD and Bluray... The very first HDVD players were to my eyes superior to the Bluray players.. I went ahead bought the second generation Toshiba and the Pioneer Elite Bluray player... Both have served me well through the years..
I am not able to see ANY difference between the Elite albeit a relatively old model and a PS3 on BluRay.. Is this the experience of the majority? Is there a difference between 24 and 60 fps.. What to look for in a top flight BluRay player? Last but not least are there legal ways to rip Bluray to HDD?

goneten

03-01-09, 10:37 AM

I also do not see any real visual PQ difference between players regardless of cost via HDMI[snip]

I agree. The only major differences I've noticed is on standard definition material.

Regards,

sierraalphahotel

03-01-09, 10:40 AM

Ill bite.

I also do not see any real visual PQ difference between players regardless of cost via HDMI " But"
there are some reasons to be concerned or at least I have been told. Depending on how HDCP is handled in the video path it can have an effect on PQ. You also do not know what players are giving us true direct 1080p24 right off the disc, only the manufacture would know for sure. What about the players that have video processing features such as brightness, gamma, sharpness etc. The signal from those players are definitely going through an additional pre processing stage before it leaves the player. While you may set the sharpness to 0
the manufacture may want you to see a sharper image so 0 might actually be +1 inside, you never know.
I own an HD SDI player for one reason it does ensure I am getting the information right off the disc exiting the player via the shortest video path.

I have not compared enough players to offer much opinion, but although in theory the output from players "should" all be the same over HDMI (i.e. what is on the disc) the reasons Alan outlines would make it hard to rule out differences existing between players.

When I borrowed Pioneer's very first blu-ray machine a while back, it appeared to me that less global sharpening was being applied by the Pioneer compared to my PS3. During certain scenes in Blade Runner, the film grain was really exaggerated on the PS3 compared to the Pioneer, even though the settings on my display remained the same. This was the only occaison I could point out a worthwhile difference. On more recent movies they both looked spectacular.

The PS3 has certainly proved a better investment than the Pioneer for my circumstances.

Sean

Art Sonneborn

03-01-09, 12:10 PM

Art, do you still think "the question is rediculous" in view of Alan Gouger's
informed answer?????

Yes, based on the answer he gave he came right out and said no PQ differences so it is entirely consistant with my post. Literally, this is as bad as QQQ said. I bought a new hard drive for my PC because my spread sheet came out so much cleaner looking. It was as if a veil had been lifted. The black text was blacker. I even noticed that reading the text was less fatiguing despite the economy.

Art

Dennis Erskine

03-01-09, 12:59 PM

I modified my spreadsheet to output white. Absolutely reduced the stress and fatigue from the 1's and 0's turning to 8's and 3's.

Dennis Erskine

03-01-09, 01:06 PM

I have no doubt the some manufacturers are not being completely forthcoming with respect to just exactly what they are doing internally. I suspect a shortcut or two. On the other hand, I also suspect many who are doing some arm waving about this sort of thing don't even know what the specified voltage should be on the video outputs (and, of course, your video calibrator did measure that before calibrating everything. Right?)

Gary Murrell

03-01-09, 01:09 PM

odyssey

03-01-09, 01:25 PM

This is a very good question. Unless you want to use the player controls to correct a problem, the usual goal is to minimize processing and conversions in the player. You also have to look at the whole system to minimize conversions.

A good example of a potential problem is the first generation Pioneer Elite BD player. The usual best output choice is YCbCr. This is the format of the disc data. If it's converted to RGB in the player, it's converted back to YCbCr in some (most?) projectors for processing and back to RGB for display. If you select YCbCr output in the player, this multiple conversion is avoided. That's the theory. The reality with that Pioneer model is that there is a YCbCr to RGB conversion tha can't be avoided. If you select YCbCr output, you have YCbCr to RGB to YCbCr. It's better to choose RGB output with this player. This type of information is not available and was found only when the HD-SDI mod was developed. Instead of the expected YCbCr going to the HDMI transmitter, it was found to be RGB. This player is also one of the exceptions to the HD-SDI being safer rule since HD-SDI is YCbCr and has a dual conversion with this player.

Talking about HD-SDI, we are having problems with the Pioneer 09 mod. If anyone has access to the documentation for the Panasonic MN864707 HDMI chip, please PM me.

Barry Allen

03-01-09, 01:37 PM

I agree. The only major differences I've noticed is on standard definition material.
When shopping for a Blu-ray player, how they perform on SD-DVDs can be an important consideration for those with existing DVD collections. Not all Blu-ray players are created equal in that regard.

FrantzM

03-01-09, 02:08 PM

Gary Murrell

03-01-09, 03:48 PM

Hi

So the thread is mixture of levity and seriousness bu there are real issues ...

The real issues to me are:
Are there difference between BD Players?
What should one look for when purchasing a BD Player?
If HD-SDI is THE solution, how does it deal with HDCP?

These questions have been prompted by the quasi-disappearance of movie theaters where I live. HT has, thus,
taken a whole different meaning for me. I love movies and have to move to the Big leagues..

ill be glad to address this, there are major differences between BD players the reason is not simple, the differences include decoder quality, internal processing, conversions like colorspace 4:2:2 to 4:4:4 etc.

what you want to look for in a BD player is one that outputs 1080p/24 in 4:2:2 with no chroma bugs or hidden processing, this is hard to meet

where HD-SDI comes in is that it guarantees the purest cleanest 1080p/24 4:2:2 signal possible, processing is thrown aside, no colorspace conversions etc.

HD-SDI also bypasses HDCP entirely and frees up the HDMI port for audio only usage

my favorite for BD PQ right now is the Panny BD30/50 if you are talking stock form(it offers 1080p/24 4:2:2), HD-SDI makes it even better, there is a new kid on the block coming soon that may change my pick, what I have seen so far is amazing and can't wait to see HD-SDI on it ;)

can anyone guess which player I speak of? :p

-Gary

Art Sonneborn

03-01-09, 04:21 PM

The question was does a vibration free chassis make a difference in PQ ?,are any of you saying that vibration control on a digital output device makes a difference in the PQ ?:eek:

I'd really really hate to see hocus pocus entering into this.

Art

goneten

03-01-09, 04:34 PM

When shopping for a Blu-ray player, how they perform on SD-DVDs can be an important consideration for those with existing DVD collections. Not all Blu-ray players are created equal in that regard.

Exactly, hence why I mentioned the discrepancies between players on SD material. Some players can have pretty atrocious up-scaling. But in terms of Blu-ray playback, I think most of them (even the "cost-no-object" designs") are on a par. I'm certain there'll be measurable differences but that doesn't necessarily mean that there will be perceivable differences.

*Flame resistant suit on*

Regards,

Art Sonneborn

03-01-09, 04:36 PM

Originally posted by goneten

Exactly, hence why I mentioned the discrepancies between players on SD material. Some players can have pretty atrocious up-scaling. But in terms of Blu-ray playback, I think most of them (even the "cost-no-object" designs") are on a par. I'm certain there'll be measurable differences but that doesn't necessarily mean that there will be perceivable differences.

*Flame resistant suit on*

Regards

I agree !

goneten

03-01-09, 04:36 PM

I'd really really hate to see hocus pocus entering into this.

This forum ? Hocus pocus ? Nah. . :)

Regards,

Jim Burns

03-01-09, 05:17 PM

Haven't read the entire post yet but wanted to answer because "little Steve" (you some times learn too much form AVS forum) thought I would not. I will read the rest and answer later tomorrow this is quality time with the girl friend.

Those that know me are expecting me to recommend something off the shelf, not this time. I think a HTPC is the way to go here. I still do not know of a regular player that stands out above the rest. Does not mean it does not exist but I have not found it.

Finding an above average off the shelf player has been an issue for me too.

FrantzM

03-01-09, 06:01 PM

I thank Gary Murell for his post. What seems to be coming out is that there ARE some differences between BD player whether they can be perceived is another story and one for which I am sure there will be sides one of which will inevitably involve DBT... I may not have perceived any differences doesn't mean that there aren't any either.. I may not know what to literally look for.
There is a difference between a technology and its implementation. That it be digital is one thing , how it is implemented is a whole different story... Also I would like to understand how one can bypass HDCP, I was under the impression that HDCP decoding was necessary to obtain a picture... How does HD-SDI deas wight HDCP decoding?

Steve Bruzonsky

03-01-09, 06:27 PM

ill be glad to address this, there are major differences between bd players the reason is not simple, the differences include decoder quality, internal processing, conversions like colorspace 4:2:2 to 4:4:4 etc.

What you want to look for in a bd player is one that outputs 1080p/24 in 4:2:2 with no chroma bugs or hidden processing, this is hard to meet

where hd-sdi comes in is that it guarantees the purest cleanest 1080p/24 4:2:2 signal possible, processing is thrown aside, no colorspace conversions etc.

Hd-sdi also bypasses hdcp entirely and frees up the hdmi port for audio only usage

my favorite for bd pq right now is the panny bd30/50 if you are talking stock form(it offers 1080p/24 4:2:2), hd-sdi makes it even better, there is a new kid on the block coming soon that may change my pick, what i have seen so far is amazing and can't wait to see hd-sdi on it ;)

can anyone guess which player i speak of? :p

-gary

oppo!!!!@@@@

Steve Bruzonsky

03-01-09, 06:28 PM

amirm

03-01-09, 06:30 PM

HD-SDI is where it is at for ultimate PQ, everything is gotten out of the way and you get a pure 4:2:2 1080p/24 signal, I wish more people could get a chance to see what this brings to the table ;)

-Gary
Seeing how the format on disc is 4:2:0, then 4:2:2 would be far from pure :). Indeed that interpolation could opt to sharpen the high frequency color or soften whether in SDI or HDMI domains.

Axatax

03-01-09, 06:34 PM

It becomes more difficult to make these types of comparisons I think, on modern displays, as the video processing in even modestly priced gear tends to mask many of the anomalies we experienced with SD source material (chroma bug, progressive flag issues, etc.).

The 24p argument assumes that every video decoder in these players works perfectly. I am skeptical of this, as even after 12 years of DVD, manufactures continue to release machines with sub-par core MPEG performance (and some of the *most* expensive players tend to be some of the worst offenders). But if there is competent processing in place any deficiencies may not be easily observable. Do these new codecs work differently enough from MPEG2 that every decoder will produce identical results given the same source material? Can *all* of the post-processing (sharpening, NR, chroma upsampling, etc.) be assumed perfect, or be completely defeated?

I personally believe that most of these HD players will produce output that is more similar than different assuming direct output of HD source material. But there is still variance in SD performance, navigation speed, analog performance, video processing, and feature set, that it's not so easy to state that any HD player with price which exceeds some arbitrary amount is automatically a "waste" of money. This *may* be the case if you're using these high-dollar players strictly as transport for HD video - but I don't think that someone purchasing a $4K Denon unit has that intent.

Steve Bruzonsky

03-01-09, 06:34 PM

http://www.avsforum.com/avs-vb/showthread.php?t=1048326

http://www.usa.denon.com/ProductDetails/4760.asp

DVD-A1UDCI

$4,500.00

"For the ultimate disc playback accuracy, Denon’s DVD-A1UDCI sets the standard in state-of-the-art audio and video reproduction. Denon’s exclusive design allows playback of popular high resolution audio formats such as SACD and DVD-Audio, and is BD-Live Ready (Firmware update available approx. Apr./09). Your CD collection will never sound better, thanks to Denon’s new AL32 advanced digital audio processing, which upconverts conventional 16-bit CDs to full 32-bit digital format, virtually eliminating low-level harmonic distortion in the process. For pristine video quality, the Silicon Optix Realta HQV processor provides superb DVD deinterlacing and upconversion to HD, along with sophisticated picture improvement algorithms. Featuring balanced stereo analog outputs, the DVD-A1UDCI is equipped with true 32-bit dual differential D/A converters for each channel, along with a full set of conventional analog 7.1 outputs. The dual parallel HDMI outputs can also be assigned with HDMI Pure Direct Mode, with one HDMI output for audio and the other HDMI output for video with higher digital clocking accuracy and improved jitter control. For installation and configuration flexibility, the DVD-A1UDCI features RS-232C serial control, and BD-Live functionality via Ethernet connection. "

Interesting?

Steve Bruzonsky

03-01-09, 06:37 PM

http://www.avsforum.com/avs-vb/showthread.php?t=1124287

Official OPPO BDP-83 Early Adoption Program Owner's Thread

Interesting. Early adopter price $499. DVD 480i over HDMI. Blu Ray 1080/24 with direct source mode for no processing with HDMI video signal at all!!!!
(concern indicated earlier by Alan Gouger that some Blu Ray players may mess and process some with the HDMI video signal).

Dennis Erskine

03-01-09, 06:58 PM

The dual parallel HDMI outputs can also be assigned with HDMI Pure Direct Mode, with one HDMI output for audio and the other HDMI output for video with higher digital clocking accuracy and improved jitter control.
Oh, oh. Here comes DougW

thebland

03-01-09, 07:00 PM

amirm

03-01-09, 08:16 PM

The 24p argument assumes that every video decoder in these players works perfectly. I am skeptical of this, as even after 12 years of DVD, manufactures continue to release machines with sub-par core MPEG performance (and some of the *most* expensive players tend to be some of the worst offenders).
Both MPEG-4 AVC and VC-1 have new "transforms" which make it a lot easier to write accurate decoders. In addition we (Microsoft) donated a set of "test vectors" (verification suite) to SMPTE as part of VC-1 standardization which chip companies use to verify their implementation. So while none of this guarantees 100% accuracy, they are major step forward.

Gary Murrell

03-01-09, 09:16 PM

Steve is correct, the Oppo it is, and don't think for one second this is some lightweight cheaply built POS, it is a big departure from the normal Oppo stuff, I am proud to own it

-Gary

Gary Murrell

03-01-09, 09:19 PM

Seeing how the format on disc is 4:2:0, then 4:2:2 would be far from pure :). Indeed that interpolation could opt to sharpen the high frequency color or soften whether in SDI or HDMI domains.

yes Amir, but we never get that 4:2:0 as there is chroma upscaling as part of the decoding process for BD, HD-DVD and DVD, what we want is 4:2:2 from a player if looking for a HDMI unit with the best PQ, HD-SDI always delivers that because it gets the decoded info before internal conversions etc.

-Gary

Art Sonneborn

03-01-09, 09:27 PM

What about the robust chassis and reduction in vibration in how it effects output quality over HDMI ?

Art

Steve Bruzonsky

03-01-09, 09:38 PM

What about the robust chassis and reduction in vibration in how it effects output quality over HDMI ?

Art

Yes, I did raise that question? I feel confident it makes a difference for those using the player to do the DA conversion and output analog audio. Maybe even if you use the player to do the DA conversion and interlacing and scaling for video. Re digital audio and video HDMI output from the player, that I do not have experience or an opinion on.

The fact that the Oppo is relatively inexpensive for what it gives, unadulterated 480i DVD over HDMI and unadulterated 1080p24 Blu Ray over HDMI, is sensational - and it ain't no $1,000, $2,000 or more!!!@@@
I too question whether a much more expensive and more vibration free chassis will make a difference here, at least for video!

amirm

03-01-09, 09:42 PM

What about the robust chassis and reduction in vibration in how it effects output quality over HDMI ?

Art

I just did a search to see who all claims this as a feature. Ran into Denon, Marantz and Sony. Interestingly enough, none claim any benefit other than Denon saying it makes the signal more "accurate."

Vibrations can cause the disc to move up and down, requiring the OPU to keep hunting to focus on the pits. For audio, the variable power consumption can impact audio clock/jitter. Same can happen for video but unlike audio, we are trying to output to a digital source so I can't see any harm in that.

So perhaps the only benefit is less chance of a read error in extreme, corner cases where the vibrations would push the OPU over the edge.

If someone can dig up any specific claim by a manufacturer, we can then try to examine that.

Axatax

03-01-09, 10:07 PM

The fact that the Oppo is relatively inexpensive for what it gives, unadulterated 480i DVD over HDMI and unadulterated 1080p24 Blu Ray over HDMI, is sensational - and it ain't no $1,000, $2,000 or more!!!@@@

This is what's known as "source direct" mode, and this is not the first player to do this (all Pioneers feature this, AFAIK, and first-gen Sonys manufactured by Pioneer).

And 480i doesn't mean unadulterated, as the last 12 years of mostly broken players have shown. This is where the mistakes tend to happen, especially since there isn't a higher level video processor in use (480i) before the output to mask some of the issues mentioned above.

Axatax

03-01-09, 10:12 PM

Steve is correct, the Oppo it is, and don't think for one second this is some lightweight cheaply built POS, it is a big departure from the normal Oppo stuff, I am proud to own it

With all the sight-unseen orders they're sure to receive, maybe they can finally hire a good industrial design firm so they can make a player that doesn't look like a cheaply built POS!

That said, I hope they reach something, as this would be a welcome departure from the horde of overpriced, under performing players.

joeycalda

03-01-09, 10:46 PM

I have had 4 Blu-ray players and I rate them as follows:

They are the Pioneer Elite
Play Station 3
First generation cheap Sony Blu ray
Recent Samsung

Picture quality Play Station and the Pioneer Elite are very similar. I purchased the Samsung just to hear the HD Audio, since my pre amplifier needs the signal to be decoded in the player and the Master DTS sounds better than basic no question, but the picture qulaity was not on par with PS3 or the Pioneer. It was not as sharp and lacked brightness. I took it back and I am waiting for the newer Pioneer.

Sound quality from the Pioneer (in the bass regions only) is more powerful with the Pioneer Elite than the PS3. I did numerous A/B and it was very easy to detect the Pioneer 10 out 10 times.

The early Sony just plain suc*ed in the Audio department.

JC

amirm

03-02-09, 12:04 AM

The early Sony just plain suc*ed in the Audio department.

JC
Was that the first generation Sony BD player? If so, that was designed by Pioneer :).

CINERAMAX

03-02-09, 12:07 AM

That spending 4k on a blue ray player is way too much.

NOT!

amirm

03-02-09, 12:17 AM

That spending 4k on a blue ray player is way too much.
NOT!
Oh, just realized which forum I was posting in :D.

Say, I didn't think the Crestron BD changer was shipping yet. How did you get your hands on three of them?

sierraalphahotel

03-02-09, 03:24 AM

So in an "ideal" world, you would use HD-SDI into your PJ where available and the HDMI audio out to your SSP processor?

Sean

Art Sonneborn

03-02-09, 08:42 AM

That spending 4k on a blue ray player is way too much.

NOT!

I thought for a minute that you had turned over anew leaf.:D

Art

kjack

03-02-09, 09:57 AM

where HD-SDI comes in is that it guarantees the purest cleanest 1080p/24 4:2:2 signal possible, processing is thrown aside, no colorspace conversions etc.I'm wondering why you think this is true? It's typically not possible to ensure the video post-processing blocks are completely bypassed on a decoding SoC.

amirm

03-02-09, 10:24 AM

So in an "ideal" world, you would use HD-SDI into your PJ where available and the HDMI audio out to your SSP processor?

Sean
Well, in an ideal world you would want HDMI to work :p. We have a standard called HDMI. We need to put pressure on suppliers to make it work. HD-SDI is not the answer.

faberryman

03-02-09, 10:40 AM

Well, in an ideal world you would want HDMI to work :p. We have a standard called HDMI. We need to put pressure on suppliers to make it work. HD-SDI is not the answer.
It depends on what the question is. Should HD-SDI supplant HDMI? No. Until HDMI suppliers "make it work" is it a good alternative? Yes.

Gary Murrell

03-02-09, 11:59 AM

I'm wondering why you think this is true? It's typically not possible to ensure the video post-processing blocks are completely bypassed on a decoding SoC.

based purely on my real world experiences of HD-SDI vs HDMI on the same player, visually seeing processing being bypassed(ringing, added sharpness etc.), colorspace conversions gone, stuff like that

-Gary

amirm

03-02-09, 12:08 PM

It depends on what the question is. Should HD-SDI supplant HDMI? No. Until HDMI suppliers "make it work" is it a good alternative? Yes.
Well, my worry is that HD-SDI is in a gray area regarding copy protection. There is no provision in AACS to allow a digital output like that. So companies can lose their AACS license to produce them (or have their devices revoked). And others creating hacks could get shut down. Even though I think HDMI is very poorly thought out standard, I don't see HD-SDI as a solution I would want to rely on.

sierraalphahotel

03-02-09, 12:08 PM

It depends on what the question is. Should HD-SDI supplant HDMI? No. Until HDMI suppliers "make it work" is it a good alternative? Yes.

Thanks for clarifying my point faberryman. Indeed, if HD-SDI acts as a true "straight off the disk" to display conduit that can't be messed with, having access to content this way would not leave us at the mercy of the player manufacturers to get it right.

Sean

amirm

03-02-09, 12:15 PM

Thanks for clarifying my point faberryman. Indeed, if HD-SDI acts as a true "straight off the disk" to display conduit that can't be messed with, having access to content this way would not leave us at the mercy of the player manufacturers to get it right.

Sean
But you have no assurance of that just because you have HD-SDI. That is just a digital connection. As Keith points out, much of the processing could have already occurred in the SoC (all-in-one decoder).

The thing HD-SDI eliminates is post processing in the HDMI transmitter (e.g. RGB conversion). So in that respect you could say it is better. But it only takes decent firmware to make sure the HDMI transceiver doesn't do bad things to the signal. I imagine if someone like sspears is involved with development of players like Oppo, there is a good chance the right things are done....

faberryman

03-02-09, 12:15 PM

sierraalphahotel

03-02-09, 12:42 PM

I see, thanks for the info. At least you could eliminate one problem with HD-SDI then. :)

Cheers,

Sean

But you have no assurance of that just because you have HD-SDI. That is just a digital connection. As Keith points out, much of the processing could have already occurred in the SoC (all-in-one decoder).

The thing HD-SDI eliminates is post processing in the HDMI transmitter (e.g. RGB conversion). So in that respect you could say it is better. But it only takes decent firmware to make sure the HDMI transceiver doesn't do bad things to the signal. I imagine if someone like sspears is involved with development of players like Oppo, there is a good chance the right things are done....

Alimentall

03-02-09, 12:46 PM

Axatax

03-02-09, 12:48 PM

Indeed, if HD-SDI acts as a true "straight off the disk" to display conduit that can't be messed with, having access to content this way would not leave us at the mercy of the player manufacturers to get it right.

But HD-SDI is not straight off the disk. The compressed source data still needs to be decoded first, and historically, this is where most of the errors occur. With HD-SDI, you bypass the output stage (DAC or HDMI transmitter), and possibly post-processing in the player, if any, depending on how the HD-SDI transmitter is installed.

Alan Gouger

03-02-09, 12:49 PM

But you have no assurance of that just because you have HD-SDI. That is just a digital connection. As Keith points out, much of the processing could have already occurred in the SoC (all-in-one decoder).

Good point, that is true. I have a few HD SDI players and one of them still allows me to use the on board processing features, brightness, sharpness etc. So that is not direct thats for sure.

.

faberryman

03-02-09, 12:49 PM

I remember the massive differences between DVD players and that always surprised me, all because of the differences in MPEG decoding (I presume), so I wouldn't be surprised at all to see differences, perhaps obvious ones, in BD players. Don't care too awful much because I don't plan on ever owning one. Downloads are the real future. BD is just a diversion.
So you are just going to forego HD video content until uncompressed HD video content is available for download? Aren't you just cutting off your nose to spite your face?

kjack

03-02-09, 12:54 PM

But you have no assurance of that just because you have HD-SDI. That is just a digital connection. As Keith points out, much of the processing could have already occurred in the SoC (all-in-one decoder).

The thing HD-SDI eliminates is post processing in the HDMI transmitter (e.g. RGB conversion). So in that respect you could say it is better. But it only takes decent firmware to make sure the HDMI transceiver doesn't do bad things to the signal. I imagine if someone like sspears is involved with development of players like Oppo, there is a good chance the right things are done....If the HD-SDI tramsitter chip tapped into the connection between the SoC decoder and a video post-processing chip, then any processing done by the video post-processing chip is also taken out of equation. But as I pointed out earlier, all SoC decoders do the same type of video post-processing these days, so that's not taken out of the equation. For example, I know one BD player manufacturer that tweaks the gamma curve on the SoC decoder, so using HD-SDI is not going to get around that.

Here is a list of the typical processing done inside the SoC decoders before any video data is output from it...

http://www.avsforum.com/avs-vb/showpost.php?p=15916882&postcount=222

sierraalphahotel

03-02-09, 01:38 PM

Thank you'all for the information. Interesting and educational.

Sean

FrantzM

03-02-09, 01:40 PM

Hi

Extremely interesting discussion .. The basic original question has not yet been answered. Allow me then to rephrase (apologizing in advance to Steve Bruzonsky)... Are there VISIBLE differences between BD players? If yes which one you thik are better and why? I will put the Audio output questions out for now. I have an Oppo DVD and like its picture.. Would not mind acquiring the BD player. I would also add that Sturdy construction is a virtue regardless of the rationale. I need a beefy well made transport that can be used day in and out I just broke one of these flimsy PC platters... :(

Jason Turk

03-02-09, 01:49 PM

Steve, a vibration free chassis is very important with digital too. If there's a lot of vibration some 2's or 3's or maybe even 8's might slip into the signal. You see, with all the vibration a 0 or 1 might be interpreted as a 2, 3, or 8. And there's nothing worse than a 0 or 1 being read as an 8. Then again, I heard you convinced your wife years ago to interpret your 3" as 8", so maybe an HDMI source that sends out 8's is just what you want.

Ouch.

mmiles

03-02-09, 02:04 PM

GM said...

"can anyone guess which player I speak of?"

No, so tell me!

Steve Bruzonsky

03-02-09, 02:06 PM

Art Sonneborn

03-02-09, 02:23 PM

So over HDMI we are seeing differences in PQ in BD players ? Is the robust chassis and vibration question and it's effect on PQ over HDMI in BD players answered ?

Art

mlang46

03-02-09, 02:57 PM

Yes, based on the answer he gave he came right out and said no PQ differences so it is entirely consistant with my post. Literally, this is as bad as QQQ said. I bought a new hard drive for my PC because my spread sheet came out so much cleaner looking. It was as if a veil had been lifted. The black text was blacker. I even noticed that reading the text was less fatiguing despite the economy.

Art

Even though I find Art to be MTF deficient I have to agree with him that the difference between blue ray players through the HDMI output with different vibration isolation chassis is non existent

Each blue ray player has a split optical head which ,I by the way designed and invented 25 years ago, that has a tracking servo in both lateral directions and a focus servo which controls and centers the tracking and focusing lens. These servos are so fast that normal acoustic vibrations will not effect the digital output. Either you get a complete skip or no degradation in the signal at all. That's the joy of digital.

Art Sonneborn

03-02-09, 03:02 PM

Even though I find Art to be MTF deficient

I've heard of that term some place.:D

Art

twenty/twenty

03-02-09, 03:05 PM

[QUOTE Either you get a complete skip or no degradation in the signal at all. That's the joy of digital.[/QUOTE]

What do you mean by complete skip?

joeycalda

03-02-09, 03:06 PM

So over HDMI we are seeing differences in PQ in BD players ? Is the robust chassis and vibration question and it's effect on PQ over HDMI in BD players answered ?

Well I for one have seen and heard big differences (price not neccasarily guaranteing performance) but the Pioneer Elite seems to be at the top of both catergories IMO.

amirm

03-02-09, 03:44 PM

Each blue ray player has a split optical head which ,I by the way designed and invented 25 years ago, that has a tracking servo in both lateral directions and a focus servo which controls and centers the tracking and focusing lens. These servos are so fast that normal acoustic vibrations will not effect the digital output. Either you get a complete skip or no degradation in the signal at all. That's the joy of digital.
That is not the reason they would impact fidelity. The reason there may be a difference for audio, is due to power consumption of those servos. Imagine a scenario where the disc resonates every time you excite the chassis with 200 Hz. That resonance causes the pit to go in and out of focus. The servo as you correctly state, will track, however it will also draw power and in doing so, causes noise on the power supply line. That noise then potentially impacts the clock oscillators for the DAC or HDMI output, causing jitter to either increase or change spectrum. Since the distortion is correlated with what is playing, it tends to be much more noticeable than if it were constant.

The issue for this thread is that even with the above, it is hard to think of what damage it can do to video. If we had an analog CRT as the display, the jitter may manifest itself as pixels moving but for a digital device, that would not be the case.

amirm

03-02-09, 03:48 PM

How many DVD's do you own?

I have around 800

If a DVD is 4.7 GB, that's 3760 terabytes! So it would take me 4 one terabyte drives to house my collection.
I think your math is off by 1000 :).

At $100 a drive that's $400 to store my DVD collection.
OK, this part is right.

I have about 180 Blu-rays. Lets say 80 of the are BD25's and 100 are DB50's that's 7000 terabytes of data!!!!!
You are back to being off by 1000 again :).

$100 a drive that's $700 just to store my collection. To store both my DVD and blu-ray collection that's $1100 in just drives not including a player.
Not sure where you are going with that but we are in >$20K forum so I imagine those kind of numbers don't mean anything to folks hanging around here. Many will spend that much on power conditioners :D.

Art Sonneborn

03-02-09, 04:23 PM

Well I for one have seen and heard big differences (price not neccasarily guaranteing performance) but the Pioneer Elite seems to be at the top of both catergories IMO.

To what do you attribute the difference ?

Art

joeycalda

03-02-09, 06:02 PM

To what do you attribute the difference ?

I don't have a clue, but the audio piece I would use is from 300 when the main actor Leonitis kicks the messenger into the pit (scene two or three) the bass slams into my chest with the Pioneer, but not the PS3.:confused: To be clear I only hear the differnce in the bass, vocals. ambient sounds are as close to identical as I can tell. I even only switch the HDMI input cable in the pre amp. Power conditioner is the same etc..

The Samsung Blu ray picture was not as good as the PS3 and very very noticable. I played with the settings and could not figure it out. I can only think that maybe the PS3 recognizes that my pre-amp only accepts 1080p 60 and maybe the Samsung did some sort of manipulation. I wanted to keep the Samsung to enjoy the HD audio formats decoded in the player. I returned at 30 days to Best Buy ( no problems) Why I like Box stores:) for that sort of stuff. High end AV stores get upset over that stuff and rightly so.

Anyway Art I'm as confused as anyone. I have given up on trying to look for differences in AV products, but when it is extremely obvious I have to get the better product, as long as it is within my budget.

JC

Alimentall

03-02-09, 06:10 PM

If your willing to sacrafice quality for convenance then YES downloads are the future.

How many DVD's do you own?

5 or 10. Mostly music ones where I might actually want to watch them again. I even have 1 LP, just for the cool factor of owning something obsolete.

Besides, there's nothing aside from quickly advancing download speeds preventing downloads from equalling BDs.

I don't mind spending 50¢ per movie for storage, especially when I can delete something I have no interest in seeing again. It's not like music where I want to hear most CDs over and over.

Alimentall

03-02-09, 06:15 PM

The unfortunate thing is that ALL HDMI products should have the option of passing the encoded MPEG stream from the disc as well as the encoded audio stream so that it can be unpacked in a projector or TV after being streamed wirelessly. 18mb/s isn't nearly as bad as 100mb/s

DougWinsor

03-02-09, 06:41 PM

I don't have a clue, but the audio piece I would use is from 300 when the main actor Leonitis kicks the messenger into the pit (scene two or three) the bass slams into my chest with the Pioneer, but not the PS3. To be clear I only hear the differnce in the bass, vocals. ambient sounds are as close to identical as I can tell. I even only switch the HDMI input cable in the pre amp. Power conditioner is the same etc..

The Samsung Blu ray picture was not as good as the PS3 and very very noticable. I played with the settings and could not figure it out. I can only think that maybe the PS3 recognizes that my pre-amp only accepts 1080p 60 and maybe the Samsung did some sort of manipulation. I wanted to keep the Samsung to enjoy the HD audio formats decoded in the player. I returned at 30 days to Best Buy ( no problems) Why I like Box stores for that sort of stuff. High end AV stores get upset over that stuff and rightly so.

The power conditioner would not matter, I would check your settings since it sounds like you have something turned on or off that would cause a difference.

faberryman

03-02-09, 06:46 PM

Dennis Erskine

03-02-09, 07:19 PM

I even have 1 LP,
Just one? Want some of mine?

faberryman

03-02-09, 07:30 PM

Just one? Want some of mine?
He's unlikely to have a turntable. He's waiting until you can just download LPs. It's the future.

goneten

03-03-09, 02:13 AM

FrantzM

03-03-09, 09:18 AM

So......What to conclude... PS3 is enough and provide the exact same results as any other player on the market? There IS NO discernible differences between Blu-Ray players? Just to let you know: as of last year it was not possible to test jitter on HDMI; see this post (http://www.avsforum.com/avs-vb/showpost.php?p=15952420&postcount=151)... There is a lot to learn on HDMI a lot more than some think... It is far from the perfect protocol many think it is

Art Sonneborn

03-03-09, 11:15 AM

So......What to conclude... PS3 is enough and provide the exact same results as any other player on the market.

Correct !:)

Art

Alimentall

03-03-09, 11:26 AM

The PS3 is the most capable piece of junk on the market. But it is a piece of junk ergonomically, usability, reliability wise, design wise, etc. We spend a significant amount of time running to people's homes to make them work again and again and again because they are hard for most people to use and update.

FrantzM

03-03-09, 11:29 AM

Art

Since you changed your avatar you, also have changed and gotten real mean!! :D

Art Sonneborn

03-03-09, 12:00 PM

Art

Since you changed your avatar you, also have changed and gotten real mean!!

Sorry, I've been attacked on so many threads by folks with serious agendas etc that I've just taken a stance that is consistant but unfortunately increasingly more that way.:o

Art

FrantzM

03-03-09, 12:12 PM

Sorry, I've been attacked on so many threads by folks with serious agendas etc that I've just taken a stance that is consistant but unfortunately increasingly more that way.:o

Art

I've edited my previous post... Seriously even with your PJ you have not been able to see any differences? Neither have I but as I stated earlier my experience with BD player is very limited and my PJ is far from the current SOTA...

mlang46

03-03-09, 12:54 PM

[QUOTE Either you get a complete skip or no degradation in the signal at all. That's the joy of digital.

What do you mean by complete skip?[/QUOTE]

I mean the track has been skipped or a bit dropped.

Art Sonneborn

03-03-09, 02:02 PM

I've edited my previous post... Seriously even with your PJ you have not been able to see any differences? Neither have I but as I stated earlier my experience with BD player is very limited and my PJ is far from the current SOTA...

No difference in PQ with three different BD players.

Art

Steve Bruzonsky

03-03-09, 02:11 PM

No difference in picure quality for me in first using a Panasonic BD30K and more recently a Panasonic BD35K.

Interesting that the Pioneer Elite 09 and upcoming Denon Blu Ray playes have two HDMI outputs touted as one for video and one for audio. As though that will improve performance. I admit I am skeptical on that, because I would think all they are doing is splitting/amplifying one HDMI signal into two HDMI signals/outputs. Not like they can take the HDMI audio/video signal and separate it into separate HDMI audio and video components, dejitter, etc. Or can they?????

FrantzM

03-03-09, 02:20 PM

Curious why did you acquire the 35K? Were you under the impression that it would be superior? What about sound quality?

Steve Bruzonsky

03-03-09, 02:26 PM

Curious why did you acquire the 35K? Were you under the impression that it would be superior? What about sound quality?

Gotta real good price and moved the 30K to another system in my home. Also the 35K is BD Live 2.0, too! Didn't get it expecting any better or different audio or video.

amirm

03-03-09, 02:41 PM

Not like they can take the HDMI audio/video signal and separate it into separate HDMI audio and video components, dejitter, etc. Or can they?????
They can. To the extent one of the transmitters doesn't have video fed to it, then it can certainly help the audio. Keep in mind that audio and video are seperate as they come from the decoder. So steering one into one transceiver and the other into another, is pretty easy.

I have not dug into HDMI spec enough to know if it can run without video. But even if it cannot, they can always send out pure black video as to not have it change constantly.

Now, which AVR or processor can merge two HDMI ports into one and not back out any improvement in above?

faberryman

03-03-09, 02:41 PM

Not like they can take the HDMI audio/video signal and separate it into separate HDMI audio and video components, dejitter, etc. Or can they?????
Meridian yes, Denon doubtful.

thebland

03-03-09, 02:44 PM

I have not dug into HDMI spec enough to know if it can run without video. But even if it cannot, they can always send out pure black video as to not have it change constantly.

I think it requires some sort of video stream.. Lumagen, when sending audio only via one of the 2 HDMI outputs, also sends 'blank video' at 1080i.. I think it was discussed in the Lumagen beta forum and that Jim said a video signal must accompany an audio one... Not 100% though..

faberryman

03-03-09, 02:59 PM

I think it requires some sort of video stream.. Lumagen, when sending audio only via one of the 2 HDMI outputs, also sends 'blank video' at 1080i.. I think it was discussed in the Lumagen beta forum and that Jim said a video signal must accompany an audio one... Not 100% though..
The audio piggybacks on the video so you need to either have your display on or have an HDMI sink link the Radiance to get audio over HDMI.

Michael Grant

03-03-09, 03:11 PM

I have not dug into HDMI spec enough to know if it can run without video. But even if it cannot, they can always send out pure black video as to not have it change constantly.Yeah, audio is sent over the video blanking interval.

Not only do you have to send a video signal of some sort, the video resolution determines the available audio bandwidth. For high-res multichannel you actually have to send an HD video stream, I believe.

For synchronization purposes I can't see it being practical to use a different resolution than it was originally tied to. I mean, a design that splits, say, a 1080p24 video signal and the 7.1 LPCM audio data, re-attaches the audio to a 720p24 video stream seems prone to design error. So in all likelihood the video format selected for the "pure audio" stream is going to be exactly the same as it was before the split. I could be wrong about this though.

Furthermore, from an analog signal transmission standpoint, blanking out that video signal doesn't help as much as you might think. That's because the HDMI signal spec scrambles the video data to ensure that there aren't long strings of 1s or 0s in a row, and there will be plenty of nonzero packet header and ECC bits left.

As far as I can tell, without more information to justify it, this notion that splitting the audio from the video seems just a bit more marketing hogwash. You can get the same bang from your buck with a simple 1x2 repeater.

robena

03-03-09, 03:20 PM

ee it being practical to use a different resolution than it was originally tied to. I mean, a design that splits, say, a 1080p24 video signal and the 7.1 LPCM audio data, re-attaches the audio to a 720p24 video stream seems prone to design error. So in all likelihood the video format selected for the "pure audio" stream is going to be exactly the same as it was before the split. I could be wrong about this though.

I have an Edge processor that does exactly that (from what I read), feeding my ML40 a 720p signal.

I have been using various HDMI splitters before, and I always had audio drops. With the Edge, audio drops have disappeared.

amirm

03-03-09, 03:25 PM

For synchronization purposes I can't see it being practical to use a different resolution than it was originally tied to. I mean, a design that splits, say, a 1080p24 video signal and the 7.1 LPCM audio data, re-attaches the audio to a 720p24 video stream seems prone to design error. So in all likelihood the video format selected for the "pure audio" stream is going to be exactly the same as it was before the split. I could be wrong about this though.
From sync point of view, it would not only have to be the same resolution but driven from the same video clock. Otherwise, you lose AV sync over time.

Furthermore, from an analog signal transmission standpoint, blanking out that video signal doesn't help as much as you might think. That's because the HDMI signal spec scrambles the video data to ensure that there aren't long strings of 1s or 0s in a row, and there will be plenty of nonzero packet header and ECC bits left.
What happens post HDMI transmitter is an issue in the receiver. To the extent the HDMI transceiver is not having a high frequency video signal constantly changing, one can imagine it results in a more stable situation assuming whoever designed it, didn't screw up other things.

You are right that the the receiver still sees a dynamic signal. However, if that signal is constant (i.e. doesn't change from frame to frame) then your ear is less likely to be bothered by it.

As far as I can tell, without more information to justify it, this notion that splitting the audio from the video seems just a bit more marketing hogwash. You can get the same bang from your buck with a simple 1x2 repeater.
I agree that a lot has to be done right for this to be a real benefit. Until then it does remain a marketing thing...

LJG

03-03-09, 03:32 PM

robena

03-03-09, 03:35 PM

From sync point of view, it would not only have to be the same resolution but driven from the same video clock. Otherwise, you lose AV sync over time.

That seems logical, but the DVDO site (http://www.anchorbaytech.com/dvdo_edge/support.php#faq4) gives this information about the Edge:

4. What signals can the EDGE output?

EDGE has one HDMI 1.3 output that outputs both audio and video. The second HDMI output only carries audio, with blank 720p video, which is intended to carry audio to a connected Audio/Video Receiver.

And as I posted before, no audio problems at all.

Glimmie

03-03-09, 06:11 PM

From sync point of view, it would not only have to be the same resolution but driven from the same video clock. Otherwise, you lose AV sync over time.

What happens post HDMI transmitter is an issue in the receiver. To the extent the HDMI transceiver is not having a high frequency video signal constantly changing, one can imagine it results in a more stable situation assuming whoever designed it, didn't screw up other things.

You are right that the the receiver still sees a dynamic signal. However, if that signal is constant (i.e. doesn't change from frame to frame) then your ear is less likely to be bothered by it.

I agree that a lot has to be done right for this to be a real benefit. Until then it does remain a marketing thing...

The data stream is a fixed format. You don't just drop the video away. And furthermore it makes no difference if you send balck video or a busy picture. As stated above the data is scrambled anyway for HDCP. HDMI AFAIK does not do a polynomial scrambling as it has a dedicated clock pair. But HDSDI and SDI do in fact scramble for the sole purpose of clock recovery - nothing to do with copy protection.

The signal is changing at the rate of the clock signal. It doesn't matter if the is no picture or sound or video and audio of a full symphony.

I realize some people here want to see an "audiophile" grade HDMI port. Sorry it doesn't work that way. It either meets the HDMI spec or it doesn't. Jitter in video streams is corrected by FIFO's so any jitter is reclocked to the limits of the receiver PLL.

Glimmie

03-03-09, 06:38 PM

That is not the reason they would impact fidelity. The reason there may be a difference for audio, is due to power consumption of those servos. Imagine a scenario where the disc resonates every time you excite the chassis with 200 Hz. That resonance causes the pit to go in and out of focus. The servo as you correctly state, will track, however it will also draw power and in doing so, causes noise on the power supply line. That noise then potentially impacts the clock oscillators for the DAC or HDMI output, causing jitter to either increase or change spectrum. Since the distortion is correlated with what is playing, it tends to be much more noticeable than if it were constant.

The issue for this thread is that even with the above, it is hard to think of what damage it can do to video. If we had an analog CRT as the display, the jitter may manifest itself as pixels moving but for a digital device, that would not be the case.

Sorry but I have to disagree with this theory as well. Specifically the power supply part. These power supplies are well regulated. In addition the PLL in a high quality design will have a dedicated regulator or at least be activily filtered to ensure pure DC to the circuit. Even a cheap player probably has at least a simple RC or LC filter in the PLL power rails.

I would be far more convinced the mechanical vibration could stress the focus servo beyond it's correction bandwidth than cause any issue with the units power busses.

There will always be those who think placing their BluRAy player on expensive cones or other elevation devices will make it look and sound better but just as in CD players, this has no scientific merits.

Now an analog turntable - thats another story!

Michael Grant

03-03-09, 06:55 PM

I have been using various HDMI splitters before, and I always had audio drops. With the Edge, audio drops have disappeared.Well there you go... that's important and useful info. Certainly, if you can drop down to 720p, you're reducing the bandwidth required to carry the audio, and that is in theory a more robust result. I just figured (wrongly) that it would be too much of a pain to do.

amirm

03-03-09, 07:03 PM

The data stream is a fixed format.
I don't understand what point are you making with this.

And furthermore it makes no difference if you send balck video or a busy picture.
I tend to disagree :). Let me explain it this way. In an ideal situation, the receiver would only get audio and nothing else. Any other signal, especially a high frequency video signal, is going to, through cross-talk, leak into the DAC (through its clock). We are trying to lower the chances of that.

As stated above the data is scrambled anyway for HDCP. HDMI AFAIK does not do a polynomial scrambling as it has a dedicated clock pair. But HDSDI and SDI do in fact scramble for the sole purpose of clock recovery.
We wouldn't necessarily need HDCP for the audio channel although that would limit us to 16-bits.

The signal is changing at the rate of the clock signal. It doesn't matter if the is no picture or sound or video and audio of a full symphony.
It might matter at macro level.

I realize some people here want to see an "audiophile" grade HDMI port. Sorry it doesn't work that way. It either meets the HDMI spec or it doesn't. Jitter in video streams is corrected by FIFO's so any jitter is reclocked to the limits of the receiver PLL.
I see where the issue is. You are focusing at the cable ends, we are looking at the big picture. :).

The PLL does track the HDMI clock. But at some point, we generate another clock driven from it for audio. Assuming that clock is immune to HDMI cable jitter (which is not a good assumption but let's go with it), the audio clock can get impacted by other activity in the system.

To the extent I have a totally seperate audio subsystem in a high-end processor, lack of video samples changing every pixel is helpful in reducing distortion. I guarantee you that I can measure their impact on power supply rails no matter how much you decouple the circuit or filter it. The pulses can also leak in other ways. This is why processors have modes to turn off video data paths or even front panel displays for better audio. Everything is interconnected even if it seems that it is not.

Yes, having black doesn't mean the circuits are quiet. They are still counting pixels, etc. But the level of activity is far less than real video coming at it.

Of course, in the world of mass market products the above doesn't matter. But if you are talking about spending a ton of money for the last bit of quality, then it is fair consideration. In theory at least :).

But sure, the interface has many faults. No one here is trying to defend HDMI. Just saying that if something can be done about its faults, it should be looked at. If after someone builds it, we measure it and listen to it and makes no difference, then fine.

Glimmie

03-03-09, 07:20 PM

I don't understand what point are you making with this.

I tend to disagree :). Let me explain it this way. In an ideal situation, the receiver would only get audio and nothing else. Any other signal, especially a high frequency video signal, is going to, through cross-talk, leak into the DAC (through its clock). We are trying to lower the chances of that.

We wouldn't necessarily need HDCP for the audio channel although that would limit us to 16-bits.

It might matter at macro level.

I see where the issue is. You are focusing at the cable ends, we are looking at the big picture. :).

The PLL does track the HDMI clock. But at some point, we generate another clock driven from it for audio. Assuming that clock is immune to HDMI cable jitter (which is not a good assumption but let's go with it), the audio clock can get impacted by other activity in the system.

To the extent I have a totally seperate audio subsystem in a high-end processor, lack of video samples changing every pixel is helpful in reducing distortion. I guarantee you that I can measure their impact on power supply rails no matter how much you decouple the circuit or filter it. The pulses can also leak in other ways. This is why processors have modes to turn off video data paths or even front panel displays for better audio. Everything is interconnected even if it seems that it is not.

Yes, having black doesn't mean the circuits are quiet. They are still counting pixels, etc. But the level of activity is far less than real video coming at it.

Of course, in the world of mass market products the above doesn't matter. But if you are talking about spending a ton of money for the last bit of quality, then it is fair consideration. In theory at least :).

But sure, the interface has many faults. No one here is trying to defend HDMI. Just saying that if something can be done about its faults, it should be looked at. If after someone builds it, we measure it and listen to it and makes no difference, then fine.

Are you trying to say digital hash gets into the analog circuits. Well yes it does and is difficult to filter out. A really good design would encapsulate the analog circuitry in a shielded enclosure with a dedicated power supply feeding it. In fact doesn't the Poineer 09 do just this?

But be assured enough digital hash is coupled into he audio circuit from other sources. So much so that the video data noise is probably not significant. What about the control processor? This is much lower in frequency with much stronger harmonics in the audio band.

Your video data distortion theory sounds plausible however in the real world it is insignificant in relation to the other problems of mixed signal design.

Glimmie

03-03-09, 07:32 PM

Well there you go... that's important and useful info. Certainly, if you can drop down to 720p, you're reducing the bandwidth required to carry the audio, and that is in theory a more robust result. I just figured (wrongly) that it would be too much of a pain to do.

Well you need to buffer the audio packets enough to ride out the delta difference in the data rates. But in a mass produced consumer ASIC, not a big deal.

My take on these HDMI audio problems is crappy implementation or HDCP issues in the audio device. There is no reason you should need to kill the video to get error free audio. The processor manufactures are just doing this because the audio component folks can't get HDMI right.

Seems funny that HDMI audio works just fine in a Costco Visio TV but not in some high end audio gear.

amirm

03-04-09, 07:53 PM

Are you trying to say digital hash gets into the analog circuits. Well yes it does and is difficult to filter out. A really good design would encapsulate the analog circuitry in a shielded enclosure with a dedicated power supply feeding it.
The issue is not the analog stage but digital. We are trying to deal with nanosecond jitter on a 44.1Khz audio clock. If that clock jumps left or right depending on whether I have a blue pixel or red, then I have an issue. Yes, if you step back it all looks like "hash." But we are not concerned about what it looks like with a slow scan on the scope but what it does from sample to sample.

In fact doesn't the Poineer 09 do just this?
How would it do anything like what we are talking about if its HDMI receiver is handling both audio and video?

But be assured enough digital hash is coupled into he audio circuit from other sources. So much so that the video data noise is probably not significant.
That is a big leap of faith. How do we know the relative impact of each? I have clear data that turning video helps with audio fidelity. By your notion, that is impossible. Yet there it is. Besides, a good designer can deal with the other sources. But he is stuck with whatever HDMI hands to it.

What about the control processor? This is much lower in frequency with much stronger harmonics in the audio band.
The DSP is not producing harmonic in audio band. Any DSP would be running in Mhz and not Khz. But your point is correct that its digital interactions can also cause jitter. However, we can do something about it as we design the processor. For example, I can make sure that the load on the DSP stays constant so that we don't jump from ideal to full on all the time, causing corrolated jitter on the clock.

Your video data distortion theory sounds plausible however in the real world it is insignificant in relation to the other problems of mixed signal design.
For high-end reproduction of audio, if it is plausible, that is all we need to work on :). I can't sit here and tell you how bad the HDMI audio situation is because when I went searching for equipment to measure it, I couldn't find any. Until there is real measurements telliing that I don't start with huge jitter before I get to later stages, I think it is fair to keep some hope that we can do better than we are right now.

Glimmie

03-04-09, 08:07 PM

The issue is not the analog stage but digital. We are trying to deal with nanosecond jitter on a 44.1Khz audio clock. If that clock jumps left or right depending on whether I have a blue pixel or red, then I have an issue. Yes, if you step back it all looks like "hash." But we are not concerned about what it looks like with a slow scan on the scope but what it does from sample to sample.

The DSP is not producing harmonic in audio band. Any DSP would be running in Mhz and not Khz. But your point is correct that its digital interactions can also cause jitter. However, we can do something about it as we design the processor. For example, I can make sure that the load on the DSP stays constant so that we don't jump from ideal to full on all the time, causing corrolated jitter on the clock.

I have clear data that turning video helps with audio fidelity. By your notion, that is impossible. Yet there it is. Besides, a good designer can deal with the other sources. But he is stuck with whatever HDMI hands to it.

1) DVD and BluRay are not 44.1khz but are 48khz. This is due to the required clock lock to video rates. The clock phase is not going to jump based on different video data combinations. The 48K clock is divided down from the pixel clock - it has to be as the data is synchronous to it. The only video format that used 44.1 was laser disk. But there the digital audio stream was on a dedicated FM carrier with no relationship to the video FM carrier or the base audio FM carriers either. In a multeplexed stream such as HDMI, the data packets must all be clock locked.

2) The "control processor" I am talking about is the internal computer that controls the device. Like sliding the disk carriage in and out. These do run in the KHZ range. Sure their master clock may be tens of mhz but the actual SPI and Ic2 control busses run in the KHZ range.

3) I explained that in the other post. It seems to me based on the reports in this forum that most audio only HDMI implementations are not designed properly. So yes, in this case blanking the video may help. But that's not the fault of the HDMI standard.

SDi and HDSDI both can carry embedded AES audio. As SDI and HDSDI are single wire transport protocols, the data is inhierently jittery. The clock is extracted from the data stream and relies on the scrambling of the bits to minimize excessive blocks of ones or zeros. Based on your logic that jitter in the stream affects the audio qualiy, then how does emebedded audio in SDI work? I'll tell you how as I design broadcast systems and products for a living. The reclocking arrests the jitter. As long as you can recover the data crossings, you can recover the data with full accuracy. This has been done for years with SDI. Yes we worry a lot about jitter but not as it upsets subjective picture and sound quality. Because it doesn't. Excessive transport stream jitter means complete data loss plain and simple. FWEIW, HDMI should be far superior to HDSDI in this respect as it has a dedicated clock line. So the residual jitter to the receiver should be very low.

Digital audio packaged with video is a different animal than that of plain CD. The clocks are derived from the pixel clock. DVD and Bluray don't have these jitter issues due to the strict timing requirments of the video processing chain. If I understnd you right you are claiming that changes in other portions of the multiplexed data stream effect the decoded audio quality. I just don't buy it other than hash bleeding into the analog circuits as I outlined above. Now of course if your demultiplexer is not framing the packets properly, you will have a lot of signal distortion across all the signals being carried. But that is teh typical digital cliff effect and quite obvious.

Your theory will receive rave reviews in stereo and home video magazines as most readers love to hear about all the perceived problems with their equipment. They can't come around to the idea that some things previously at fault in analog systems make no difference in performance with digital technologies.

amirm

03-04-09, 09:58 PM

1) DVD and BluRay are not 44.1khz but ar 48khz. This is due to the required clock lock to video rates.
So we are down to nitpicking I see :). In that case, I will turn the tables and tell you that sample rates up to 96 Khz are required in Blu-ray players. It all depends on what the content is encoded at. I simply picked one example.
The clock phase is not going to jump based on different video data combinations. The 48K clock is divided down from the pixel clock - it has to be as the data is synchronous to it.
Yup and it will suffer from jitter just the same. The synchronous nature only applies to ability to extract the data, but not its absolute timing. Here is a good link to read more: http://www.tnt-audio.com/clinica/jitter1_e.html. It is an old article but explains nicely in clear language how you can wind up with jitter even when you drive the clock as you state and use a PLL as you explain below.
2) The "control processor" I am talking about is the internal computer that controls the device. Like sliding the disk carriage in and out. These do run in the KHZ range. Sure their master clock may be tens of mhz but the actual SPI and Ic2 control busses run in the KHZ range.
You are way behind the times my friend :). The type of processors used in BD players are far more powerful. Gone are the days of the little micro lighting up the front panel on a CD player and controlling the drive. Indeed, there are a number of processors in a Blu-ray decoder, all running at hundreds of MHz. Here is an example processor from Sigma Designs which powers a number of Blu-ray players: http://www.sigmadesigns.com/public/Products/SMP8640/pdf_files/SMP8640_br.pdf

* 333 Mhz Audio DSPs (3 of them!)
* 667 Mhz MIPS
* 333 Mhz MIPS CPU

Here is the Broadcom part used in Samsung and some other BD players:http://www.broadcom.com/collateral/pb/7440-PB02-R.pdf

They don't give you the CPU speed directly but you can deduce it is not in Khz range by:

* Dual 333/400-MHz 32-bit DDR2 interface

You are not going to find any low-end micro like you are envisioning. BD-J requires a ton of horsepower as do decoding of all the advanced audio formats in multi-channel. Even the front-end runs in MHz region given the fact that the Blu-ray drive spins at > 48 Mbit/sec.
SDi and HDSDI both can carry emebdded AES audio. As SDI and HDSDI are single wire transport protocols, the data is inhierently jittery. The clock is extracted from the data stream and relies on the scrambling of the bits to minimize excessive blocks of ones or zeros. Based on your logic that jitter in the stream affects the audio qualiy, then how does emebedded audio in SDI work?
You mean when they don’t use house clock to sync everything together? If so, then yes, they also suffer from jitter if they attempt to convert the samples to audio as opposed to moving them from device A to device B. Keep in mind that we do not have house sync in consumer players.
I'll tell you how as I design broadcast systems and products for a living.
Ah, time to recite our resumes, eh? :) So here is a bit of mine. I used to be VP engineering at two broadcast video companies (Abekas and Pinnacle Systems). While I didn't do hands on design there, I am very familiar with the space and standards used. Two of the products I managed won technical Emmy awards. So you could say we share a common experience in that front.
The reclocking arrests the jitter. As long as you can recover the data crossings, you can recover the data with full accuracy.
Again, we are talking past each other. We are not talking about whether you can recover samples correctly. We are talking about whether the timing of the output clock is impacted or not. Read the above article and see the example where RF noise on a S/PDIF cable causes jitter!
This has been done for years with SDI. Yes we worry a lot about jitter but not as it upsets subjective picture and sound quality. Because it doesn't. Excessive transport stream jitter means complete data loss plain and simple.
We are not talking about excess jitter. Nor are we talking about jitter in a communication channel. We are talking about audio samples not being converted to analog at precise time that were captured. If you ever so slightly change their positions, you make the system non-linear and create harmonic distortion. Perfect clock does not exist in real world. No PLL cleans up all jitter. But you can take steps to reduce jitter.
I think you have read too many stereo magazine articals about jitter in CD players. Most of those articals are wrong from an electrical engineering perspective and furthermore DVD and Bluray don't have those issues due to the strict timing requirments of the video processing chain.
Please, ask me who I am before you make assumptions about me :). I am an electrical engineer and have been in audio, video, computer, network, etc. field for 40+ years. I have also been lucky to have had jobs which allowed me to have the best toys in the world to play with such things and gain real world experience in addition to my own engineering know-how. In my last job at Microsoft, I helped drive the specs for HD optical formats and technology from my group ships in every Blu-ray player. So I don’t just read a magazine and come and post here.

The bottom line is that there is a completely different science and approach to high-end audio and video. Anyone can build something that puts out audio and video. But it takes a lot more knowledge to know if they are both right. Joe Kane would be out of a job if people knew even simple concepts of what color space to use. You wouldn't believe what we went through with Toshiba to make sure their HD DVD players programmed the HDMI transceivers to not do conversion to faulty 4:4:4, blow levels, not produce proper 24p, etc. Yup the device put out an image that impressed many but it still wasn’t right until later firmware fixes.

And there is absolutely nothing in Blu-ray spec that makes the format perform any better than DVD. It reads the data like one did from DVD and sends it out. So I don’t know what you mean by “strict timing requirements.”

Anyway, I hope you keep an open mind as you read all of this. The whole world of high-end audio/video is not made up of lunatics who hallucinate these things. There is science involved. And people who know what they are doing….

Glimmie

03-04-09, 10:12 PM

Ah, time to recite our resumes, eh? :) So here is a bit of mine. I used to be VP engineering at two broadcast video companies (Abekas and Pinnacle Systems). While I didn't do hands on design there, I am very familiar with the space and standards used. Two of the products I managed won technical Emmy awards. So you could say we share a common experience in that front.

So you are possibly Phil Bennet? You worked for Juniad Sheik? Along side with Lance Kelson, Ian Craven.

Do you want me to go back to prior Ampex days where they all came from?

I'm not just some AV wannabe either. I was Fred's VP of engineering and CTO for 15 years and hold a Drexel BSEE myself! That should be enough info to figure it out.

On second though you can't be any of the folks I named above. They all understood digital video processing to the nth degree. You must be from the Scitex days when these companies went down hill. Scitex turned Abekas into a consumer level company. Pinnicle - didn't you guys put out the Cinewave card. TALK ABOUT JITTER! Nothing could clean that up. And the response form the engineering group, that would be your group, claimed it was not designed to feed a router, only directly into an HDCAM! Huh? Thank god AJA came along with a competative product that complied with industry specs. And as far as the Pinnicle San Jose shop products, I know first hand DirecTV in Marina Del rey had big problems with the early HD servers and bad HDSDI compliance.

You mean when they don’t use house clock to sync everything together?

See it's the subtle comments. "house clock" is not video facility terminology and would not used by the names listed either. It's "house sync" or "genlock" Surely anyone involved in video equipment design to the extent you claim would have that burned into their vocabulary. House clock is a recording studio term and proble used in other industries as well. Now you have a background in audio design, that is apparent. But don't BS me when it comes to broadcast video.

P.S. that artical you posted is all baout strict audio only circuits. In none of the block diagrams do I see a FIFO to iron out data jitter. Almost all video based designes I have ever seen on that level of detail uses timing FIFOs to fix that. This is a commen technique since the vaccum days of video but the audio industry didn't need to deal with this issue until digital came along.

amirm

03-04-09, 11:04 PM

So you are possibly Phil Bennet? You worked for Juniad Sheik? Along side with Lance Kelson, Ian Craven.
No, I am not any of them. My real name is part of my alias.

Do you want me to go back to prior Ampex days where they all came from?
I prefer that we talk about the topic at hand and not each other :).

On second though you can't be any of the folks I named above. They all understood digital video processing to the nth degree.
They were experts in digital video. No doubt. But I wouldn't hire any of them design a high-end audio system. There is a difference between them and someone like Bob Stuart (Meridian founder). They are all great at what they do, but the fields are different.

You must be from the Scitex days when these companies went down hill. Scitex turned Abekas into a consumer level company.
No I am not. I left Scitex as soon as they purchased the company.

Pinnicle - didn't you guys put out the Cinewave card. TALK ABOUT JITTER! Nothing could clean that up. And the response form the engineering group, that would be your group, claimed it was not designed to feed a router, only directly into an HDCAM! Huh? Thank god AJA came along with a competative product that complied with industry specs. And as far as the Pinnicle San Jose shop products, I know first hand DirecTV in Marina Del rey had big problems with the early HD servers and bad HDSDI compliance.
You spelled Pinnacle wrong :). And I am not familiar with any of those products as I left the company many years ago. But so you know, when I arrived at Abekas, the engineers there were struggling with SDI I/O cards just the same. And got you know what for it from the networks until multiple redesigns later. And I saw the same thing at Pinnacle. The Sony silicon was a pain to use then as was the third-parties who designed the same.

P.S. that artical you posted is all baout strict audio only circuits. In none of the block diagrams do I see a FIFO to iron out data jitter. Almost all video based designes I have ever seen on that level of detail uses timing FIFOs to fix that. This is a commen technique since the vaccum days of video but the audio industry didn't need to deal with this issue until digital came along.
You can have all the FIFOs you want but it won't solve anything. The DAC has a clock that is running at the audio sampling rate *post FIFO stage*. That clock, cannot and will not be perfect. Any variations in that clock causes the audio samples to be converted to analog at the wrong time. If you like to point me to an article which shows how a DAC can have 100% accurate clock with zero jitter, I would be happy to read it and comment on it.

Glimmie

03-04-09, 11:27 PM

Gotcha!

http://www.linkedin.com/pub/5/4a7/1

Hey I'm on LinkedIn too. But my alias, "Glimmie" is one of my dogs name! Good luck.

Look, just stop it. If you want to believe in your jitter theories thats fine. But don't promote yourself as an expereinced electrical engineer here because you're not. Your background is plastered all over the net. You are a marketing guy from what I see. Your technical background is in computer software, not digital hardware design.

What kind of EE degree does your Florida Atlantic University offer in a two year span? Sounds like a community college associates degree to me. Yeah I know you are highly gifted and finished the MS program in just two years!

ChrisWiggles

03-05-09, 10:13 AM

Yeah, audio is sent over the video blanking interval.

Not only do you have to send a video signal of some sort, the video resolution determines the available audio bandwidth. For high-res multichannel you actually have to send an HD video stream, I believe.

For synchronization purposes I can't see it being practical to use a different resolution than it was originally tied to. I mean, a design that splits, say, a 1080p24 video signal and the 7.1 LPCM audio data, re-attaches the audio to a 720p24 video stream seems prone to design error. So in all likelihood the video format selected for the "pure audio" stream is going to be exactly the same as it was before the split. I could be wrong about this though.

Furthermore, from an analog signal transmission standpoint, blanking out that video signal doesn't help as much as you might think. That's because the HDMI signal spec scrambles the video data to ensure that there aren't long strings of 1s or 0s in a row, and there will be plenty of nonzero packet header and ECC bits left.

As far as I can tell, without more information to justify it, this notion that splitting the audio from the video seems just a bit more marketing hogwash. You can get the same bang from your buck with a simple 1x2 repeater.

It depends. It isn't hogwash if they can stick in a black video signal at a lower rate than the one you want for video. As someone suggested above about the Lumagen outputting a 1080i blank video soley for audio, this is beneficial if you are trying to get your video to a different location that may be quite far away (say a projector). Being forced to send 1080p60 video to an audio processor, then back a long distance to a display, it would be very very nice to be able to isolate the high bandwidth video run from a lower bandwidth blank video signal with the audio to the audio processor which may be located somewhere farther away.

But again, that's only IF the video output signal is different so you can take advantage of the lower bandwidth audio output over distance.

faberryman

03-05-09, 05:54 PM

Denon is much higher then meridian as far as engineering goes, just look at the denon ilink.How is Denon iLink superior to Meridian MHR?

mrlittlejeans

03-05-09, 06:15 PM

John Kotches

03-05-09, 06:21 PM

Denon is much higher then meridian as far as engineering goes, just look at the denon ilink.

Denon does have good engineering.

But Meridian quietly has one of the best Digital Audio engineers on the planet and I'm not referring to Bob Stuart. I'm not saying he isn't one of the best but he's not comparitively quiet. I'm talking about Rhonda Wilson, PhD.

Check her contributions to the Audio Engineering Society, then show me half of the same total by all of Denon's engineering staff as part of the AES in the same time period.

When you've done that, we can talk about engineering.

Glimmie

03-05-09, 08:50 PM

Whoa Glimmie. Attacking Amir in such a way is totally uncalled for and reflects poorly upon yourself.

Amir - You should be applauded for not sinking to such a level. And thank you for your contributions to AVS.

He opened the door, not me. He posted his employment history in great detail. I merely used free public open search utilities which anyone else could have done. If you are going to post your professional background here and it's inflated, better make sure it's not tracable.

At least I don't inflate my background. He claims 40 years experience but started college in 1980? The he claims he is an electrical engineer but only went to school for two years?

I could post the many links I found but do your own research. See how he fairs on other forums. That's all I'll say.

So I expose the truth and I'm the bad guy. Oh well, I've been there before.

P.S. Don't feel alone, I got a few PM's that chastised my behavior as well. But I got some that praised it too :)

markrubin

03-05-09, 10:10 PM

this thread starting to derail eh?

posts deleted and a member asked to leave the thread

I do hope you guys can carry on a good technical discussion

amirm

03-05-09, 10:44 PM

He opened the door, not me. He posted his employment history in great detail.
Sorry but I post that after you said "I do this for a living" as if I did not. My bad if that is what set you off :).
At least I don't lie. He claims 40 years experience but started college in 1980? The he claims he is an electrical engineer but only went to school for two years?
Not everyone learns about technology at the University. In my case, I literally grew up with electronics and audio. I think I built my first audio amplifier when I was 7 years old. Bought my first “hi-fi” gear when I was 8 after pestering my dad for three months for the money. And no, it didn't have an 8-track tape in it :D.

My older brother was an electrical engineer and taught me a ton about analog and digital design before I even finished high-school. I put this experience to use later, repairing all manner of audio/video electronics and RF equipment at the local electronics retailer while going through college. During this time I also got into personal computers (bought and Apple II in 1978) and started programming that in addition to building S-100 Z-80 PCs. Anyone remember 8-inch floppy drives?

Shortly after I started college, I managed to impress the dean of the computer science department and he hired me to run the computer lab. I went on to learn the PDP-11 operating system and programming language and wrote a bunch of tools to help the students with their assignments including a full-screen editor and front-end to the compiler. I also repaired the computer terminals we had in the lab as they would seem to die once a week. I kept that job until I finished my degree at the FAU.

Net, net, just because I started college in 1978 (not 1980 as you state), doesn’t mean that was the first day I heard of a transistor, DAC, or microprocessor. Yes, most people learn this stuff in school but I was lucky to learn the real life version years before.

As to my degree, at the time I was going to school FAU was a small university and only focused on Masters program and only the last two years of engineering for Bachelor program. They did not offer a 4 year program. You had to get the first two years done at a college which is what I did. And then transfer there for an additional two years (focused 100% on engineering as opposed to general courses) to get your 4 year degree. They later expanded the program to four years after I got my degree.

So I hope this clears both points.
So I expose the truth and I'm the bad guy. Oh well, I've been there before.
Glimmie, I hold you in high regard as a digital video designer and thought we were having a good discussion until this sidetrack. I hope we can go back to having technical discussions and not focus on each other. I trust that you see that nothing good comes out of these interactions other than angst and raised noise floor of the forum :).

kjack

03-05-09, 10:50 PM

...raised noise floor of the forum :).Maybe someday somebody will design a squelch control for forums... :)

John Kotches

03-06-09, 06:40 AM

Maybe someday somebody will design a squelch control for forums... :)

Does that work on a digital medium? ;-)

I think the ignore button, which is a form of a digital filter is about as good as it's going to get.

Now, are we going to talk about the impulse response of that filter? :D

FrantzM

03-06-09, 01:04 PM

Does that work on a digital medium? ;-)

I think the ignore button, which is a form of a digital filter is about as good as it's going to get.

Now, are we going to talk about the impulse response of that filter? :D

I have come to see that the "ignore" feature is too steep a filter... a brickwall if you will.. better use a smooth slope like the very level-headed answer given by Amirm, I know I can use such advice...

Strangely enough , I am not sure I have gotten the answer I want. it could be that at the present MOST BD players provide the same PQ it does not mean that there is no way to extract more performance from the basic design or that there isn't a player out there that would provide better performance. That is what Hi-End should be about not just high price for the sake of it as it has become, alas, customary...

amirm

03-06-09, 01:41 PM

I think you want to pick a player that "first does no harm." It has been a shocking experience to see how people can take ready recipe from a manufacturer to build a player, yet not know how to program the silicon to not screw up the data path. You would be amazed to know that folks that make the player sometimes don't subject them to standard test signals, nor how to interpret the results! If it puts out a high-def picture, it is good enough for them.

It is a shame really since for a few dollars, one can hire top notch consultants who can show them a way. You can see this working with Joe Kane and Samsung projectors. We need similar relationships to make other players work until such time as equipment makers learn the ins and outs on their own.

I have not kept in touch with sspears to know if he is working with Oppo. If he is, then I would say that player should meet the above goal better than any other.

Once there, then we can focus on the next level as asked here.

Glimmie

03-06-09, 03:49 PM

Amirm;

My problem is that you are taking a highly subjective theory without any scientific documentation and using your background to convince non technical folks of it's viability.

That is that video data transitions cause clock jitter which affects digital audio reproduction.

You said yourself you can't measure it. Which in it's self I must question. We can easily measure clock jitter into the single digit picoseconds and have been able to for years.

One thing I have learned here over the years is not to discount what people hear. Because nobody can hear exactly what someone else hears. Perhaps you hear something on BluRay and attribute it to video data causing jitter. That's fine. But unless it can be proven and repeated, it's just a theory. My point is to keep it at that.

When I tried to offer alternative support for your theory such as digital hash you just blew it off.

When we are all said and done no matter how high the sample rate, the highest frequency of interest is 20khz. Now it's far from difficult or expensive these days to measure even extremely minute details in that frequency range. Yet some folks (not saying you) are always trying to cast doubt and voodoo over these measurments. They can't accept that two different pocket calculators with vastly different price tags both produce the same correct answer. Now I realize digitalk audio processing is a bit more complicated than a calculator. But many of the same digital principles are the same. I am of course talking about uncompressed PCM audio. When we get into compression, well that is a highly subjective quality assement. But PCM is basic "in should equal out" You are offereing an interesting technical theory on advanced jitter problems but I for one don't buy it.

Steve Bruzonsky

03-06-09, 07:59 PM

amirm

03-06-09, 11:48 PM

Amirm;

My problem is that you are taking a highly subjective theory without any scientific documentation and using your background to convince non technical folks of it's viability.
First, thanks for the cordial way to continue the discussion. Much appreciated :). As to your point, we didn't get far enough for me to provide independent research in this area. I hope to make up in this post!

That is that video data transitions cause clock jitter which affects digital audio reproduction.
If I may, let’s step back and examine the question put before us. That is, whether an “audio HDMI” could be helpful in improving the audio fidelity. To understand this, we need to dissect what could cause damage to digital audio.

At high level, Nyquist theory tells us that if we sample the source at twice its maximum frequency, we can then reproduce it without loss. For this to be true though, two things need to happen:

1. The samples need to have infinite resolution. If they do not, you get what is called Quantization noise or distortion. Luckily the real world doesn’t have infinite dynamic range or zero noise floor. And we have a wonderful tool called “dither” that allows us to trade quantization noise for benign noise. For this reason, you often find me on the other side of audiophiles, arguing that “give me 24-bit or death” makes no sense in real life. We can achieve the same fidelity at much lower word length. But we digress.

2. The sample timings must be the same as the source. That is if you took a sample once a second, then the output better be precisely once a second. This is where jitter comes in so let’s expand on this.

Every audiophile has one dream: a system which does not color the source. What this translates into engineering terms is that you want the system to be “linear.” If the source gets twice as loud, you want the output to become precisely twice as loud. If a pure 1 KHz tone is fed to the amp, you want the output to be a pure 1 KHz tone and not other frequency added to it.

Now, what is a DAC? This is a device which fed samples and a clock, converts said samples to analog signal that we can then amplify and feed to the speaker to hear. An ideal DAC is 100% linear device. If you double the value of the input sample, the output must double in voltage. Sadly, no DAC is that linear, at least not all the time.

How do we get non-linearity in a DAC? Let’s consider one source at hand: jitter. Jitter is variations in the clock timing that tells the DAC to output its sample. For CD music the clock would be 44.1 KHz (assuming we are not oversampling). An ideal DAC then would have generate 44,100 samples per second precisely with no variations in each pulse. Unfortunately there is no such thing as a perfect clock. Jitter is the variations in the clock.

How would jitter cause distortion? If samples are output too early, it compresses the waveform. If it comes too late, it expands it. So in some sense, you are modulating your source now by another analog waveform (the jitter). Such a modulation generates new frequencies not existing in the original signal. This is in the form of harmonics which are multiples of the input frequencies. Presence of jitter modifies a DAC from a linear device then, into a non-linear component.

Jitter is perhaps the most complex animal in the world of audio because it can come in many shapes and sizes. Jitter can have one frequency or complex set of frequencies. And it magnitude can vary just the same. This presents an infinite set of possibilities as far as impact on audio fidelity. In general though, jitter becomes audible once its spectrum is above 200 Hz but below 20 KHz. At lower frequencies masking effects doesn’t allow you to hear the artificial sidebands created. And at greater than 20Khz, well, they should not be audible.

With introduction out of the way, we need to examine why jitter gets created in the first place. For this, we can resort to the many research and scientific papers on the topic. Here are some examples: http://www.essex.ac.uk/dces/research/audio_lab/malcolmspubdocs/C134%20Paper%20121st%20convention%20(corrected).pdf

“In practical electronic systems there are many sources of jitter that can occur, these relate to noise in oscillators, signal reflections in digital inter-connections, power supply induced effects, mutual coupling between circuits and problems associated with non-optimum ground rails. Also, in networked audio substantial jitter occurs because of the indeterminate arrival of packet data. All these sources of jitter can be smoothed if some delay is acceptable, but in practice there is always a degree of residual jitter with elements that can be periodic together with random and correlated components with the digital data.”

Translating the above, just about anything inside your audio equipment can impact clock jitter. Circuits completely unrelated to the audio system, can bleed into the clock circuit via power supply, ground planes, or even being close proximity of audio circuits. The DAC itself can even create jitter by having its input signals bleed into clock input. After all, they are only separated by a few millimeters on the piece of silicon. Considering that 250 picoseconds of jitter is all it takes to destroy the lower order bit in a 16-bit audio sample, even the slightest interference counts.

The article then goes to say:
“Uncorrelated jitter, although it can result in modulation noise, is generally believed to be more benign compared to jitter that has a correlation with the audio data or has a relationship to a periodic signal such as mains hum.”

So here, we see that how the jitter itself behaves is important. If jitter changes signature due to something that has similar frequency to the audio samples, its effect can be much more harmful. In the case of HDMI where its video circuits are running at the same multiples of audio pulse rate, the potential then exist for correlated jitter as opposed to say, random noise from the DSP decoding TrueHD stream.

Continuing on the article points out this very thing:

“Many jitter problems result directly from the numerous clocks that are distributed within digital audio systems. Logic gates inevitably produce transients on the power supply and also because of the resulting high bandwidth signals present in the ground rail, these can contaminate the associated sub-systems, this is why systems with multiple power supplies are often employed….”

Looking at other papers, there are more references on the same point: http://www.wolfsonmicro.com/uploads/documents/en/Specifying%20Jitter%20Performance.pdf

“A clean-and-simple clocking arrangement might have a free-running crystal oscillator connected directly to local ADCs and DAC chips. But such arrangements are not very common. Even in DVD players for example, the audio clocks come via a PLL (phase-locked loop), locked to 27 MHz. And in digitally connected systems, downstream devices commonly slave their audio clocks either to an incoming audio stream or to a nominated sync master. Every stage in the clocking chain can potentially contribute jitter to the derived audio clocks.

Here, the point is made that jitter travels from one stage to the other even with the presence of PLL which filters high frequency jitter, but often leaves low frequency jitter in the audio band intact.

“Audio ADCs and DACs have three important inputs; the signal input, the voltage reference, and the clock. Noise and interference on the voltage reference causes amplitude modulation, and jitter on the clock causes phase modulation. The resulting modulation products look very similar in the frequency domain. One of the authors once spent several days trying to track down a low-frequency jitter problem, only to find that it was in fact a problem of LF noise on the voltage reference.”

Above mentions another way interference finds its way into the DAC and that is in the form of reference voltage used to generate the analog output. With a 16 to 24-bit words, even small changes in the reference voltage can corrupt the low order bits. Signals from the rest of the system can not only make the reference less accurate but also modulate it with some other source such as the input signal.

“Jitter bites equipment designers most deeply when it causes a converter that should have more than 100 dB of dynamic range to deliver e.g. only 80 dB. In such cases the jitter is interacting not with the audio signal but with an internal signal such as shaped quantization noise. Early one-bit DACs were particularly sensitive to this.”

The statement above must come as a shock to people who think jitter is not something to worry about :). To be honest though, I think 99% of the population cannot hear jitter. But the last 1% can assuming they have good equipment and are not dealing with higher order problems.

So putting this all together, jitter is created by other activity in the system. To the extent that activity can be reduced, then jitter can be reduced. A video signal with its clock signal locked to audio, can be a big a source of correlated jitter. For this reason, I said we should allow for possibility that an HDMI input dedicated to audio could help with fidelity. An HDMI input that consists of black pixels only, will tend to create less activity in the input stage, resulting in less impact on the power supply rails and generate less RF energy than a video signal that would be changing pixels all the time.

Finally, instead of reading research papers, we can read comments from president and founder of Arcam (high-end audio/video company), John Dawson on this very forum: http://www.avsforum.com/avs-vb/showpost.php?p=11051494&postcount=1229
The problem with SPDIF and HDMI is that a clean audio master clock is not sent alongside the data signal. In the case of SPDIF it is buried inside the data and has to be reconstructed for use within the receiving device. Moreover the digital bitsteam can get modulated by the value (amplitude) of the digital signal, so without exceptional PLLs you can't do it cleanly. This applies to DD and DTS as well as PCM. The data is bit for bit accurate but the timing of the data pulses is variable (hence correlated jitter is difficult to eliminate).

HDMI is a bit different (and rather more complex) but you still have the problem of reconstructing a clean audio clock. In this case it has to come from the video clock - actually the TMDS clock - rather than a purely audio one.
John Dawson (ARCAM)

Gosh this got long :). But really, I have only touched the surface of this topic. How jitter is managed will give life to many, many high-end products I am sure :D.

amirm

03-07-09, 12:33 AM

Looks like Oppo may be delivering the goods on first do no harm: http://www.hometheaterforum.com/htf/ht-hardware-high-definition/283340-htf-special-review-upcoming-oppo-bdp-83-profile-2-0-universal-blu-ray-player.html#post3519331

dazzerxxx

03-07-09, 02:53 AM

"HDMI is a bit different (and rather more complex) but you still have the problem of reconstructing a clean audio clock. In this case it has to come from the video clock - actually the TMDS clock - rather than a purely audio one.
John Dawson (ARCAM)"

Is that the only method or regenerating an audio clock or one option for generating an audio clock at the sink ?

I didn't think the HDMI 1.3a spec was prescriptive in what process a manufacturer must apply to audio clock regeneration. Rather is provides a basic solution but suggests there are other alternatives.

There was an interesting article in Hi-Fi news (Feb 09) comparing performance of AVR's using the same source. HDMI jitter was measured and there were some significant variances reported. A Pioneer product tested measured very low level of jitter yet subjectively was reported as not sound a good as some of the other product that had between 54-173 x higher jitter measurements.

D

Steve Bruzonsky

03-07-09, 08:15 AM

JITTER!!!!!

I remember my first DVD player, the Sony when it first came out. Although DVDs looked better than laserdiscs, I could hardly tolerate the sound. Laserdisc sounded much better.
After a year or so, I replaced the Sony DVD player with a Theta Voyager, and my DVD sonics so much improved that I quit using laserdisc.

At that time there were arguments flying around about digital being perfect vs jitter with DVD audio as well.

It would be nice if one could pay more and get a more jitter free and better sounding and looking picture. But its not that easy. Paying more doesn't assure you anything in this regard. Like the analog video cable testing done with TDRs by our Az AV Club some years back, where as a general rule, the more expensive the video cable, the poorer the performance as tested on a TDR using the 75 ohm standard.

What's nice with the new Oppo Blu Ray player is that if you know the players involved, then you know why once can expect DO NO HARM & KEEP IT SIMPLE STUPID to at least be done. Stacy Spears and Don Munsil have been involved. For almost ten years they have done the objective DVD player testing for Secrets of Home Theater and High Fidelity. Stacy in more recent years is also on staff for Widescreen Review. In real life Stacy makes a good living as an engineer. I've personally known Stacy for years, since
I once moderated the AVS Special Guests forum, and he is tops as a person, what I would call uncorruptable!!! And the price to the public of the Oppo player will be in the $499 to $599 range. Now I don't know that the Oppo will have any special dejittering, but I am confident that it will from a video standpoint both put out a "pure" 480i video over HDMI AND for those needing deinterlacing & scaling do an excellent job therein.
Why? Because Stacy and Don are involved!!! HA!

Now we need some investors and lets have Glimmie and Amir design even a higher level Blu Ray player. HA! HA

fastl

03-07-09, 08:30 AM

....Now we need some investors and lets have Glimmie and Amir design even a higher level Blu Ray player. HA! HA....

More like a pair of boxing gloves. Really, these jitter discussions give me the jitters. The discussion is largely moot these days due to the ability of the technology to reduce jitter to levels that are essentially inaudible. Still, there are those keep bringing the topic up again and again.....

RBFC

03-07-09, 09:38 AM

There was an interesting article in Hi-Fi news (Feb 09) comparing performance of AVR's using the same source. HDMI jitter was measured and there were some significant variances reported. A Pioneer product tested measured very low level of jitter yet subjectively was reported as not sound a good as some of the other product that had between 54-173 x higher jitter measurements.

D

There are too many other factors when comparing different pieces of equipment to state that jitter level is the reason for preference.

Lee

John Kotches

03-07-09, 10:34 AM

There are too many other factors when comparing different pieces of equipment to state that jitter level is the reason for preference.

Lee

Is that the case in this test though? PCM output on a lossless track and the same gear in the same room seems like it would be a very good method for testing.

Maybe it's just me though...

amirm

03-07-09, 10:42 AM

More like a pair of boxing gloves. Really, these jitter discussions give me the jitters. The discussion is largely moot these days due to the ability of the technology to reduce jitter to levels that are essentially inaudible.
As I noted most people can't hear jitter. And there are infinite possibilities for jitter as far as waveform, spectrum, periodicity, level, correlation, etc. And if there is correlation, then what material you play makes the experiment different!

So it is an impossible job to rule out jitter effects since by definition, you would have to pick some profile to test with which is likely different than equipment you and I have.

In other words, folks that believe in jitter always have a way out of any argument like this :p.

Still, there are those keep bringing the topic up again and again.....
As long as those people have PhD in signal processing and after peer review have their papers published in AES and such, we have to choice but to at least consider that this is still a concern. :)

But at the end of the day, what matters are your ears. So do a simple test. Take two DVD players and connect them to your AVR/processor using S/PDIF two different ways:

1. With the best quality S/PDIF cable you have with the shortest length.

2. A long, cheap, *audio* cable like the free ones that come with your equipment (but be sure to piece a couple together to make them long).

Next get a good quality set of headphones and then do an A/B between #1 and #2. Pick source material which has high frequency and decays to nothing (you will need two copies of the same material). Sync thet two players and then start to compare the two by switching back and forth. Pay attention to whether the decay is the same length. And whether the highs get a little brighter or softer.

BTW, be sure to turn off the front panel display and select stereo-direct or whatever your AVR has which turns off the video circuits. If you do hear the above differences, then see if you can hear the effects of these circuits.

If you do hear a difference, then you have some explaining to do if "digital is digital." And jitter is inaudible.

Next do another test. Rip some music at 384 kbps and compare it to the original. If it sounds essentially the same to you, you can be happy that you will never hear jitter either. You can save a bunch of money on audio equipment then :D. Seriously, being able to hear slight compression artifacts also means that you are more likely to hear jitter.

FrantzM

03-07-09, 11:05 AM

I thank Amir, Glimmie and everybody else for their wonderful contribution for this is a very interesting subject.
I do not believe we are at a stage where ALL bluray players are perfect, that we will no longer be able to extract any discernible and worthwhile performance from these. It is true that most people do not care about subtle differences in PQ and VQ.. I would dare say 99.99% of the population... but the enthusiasts, Audiophiles and videophiles do... And there should be a solution for them, call it High End if you will for those who would care about calibrating a display and then "learn" to appreciate how much better their display was it is a worthwhile question to wit: Is the PQ provided by the current offerings, the best BD can do?I have my doubts...

Chuck V

03-07-09, 11:13 AM

As long as those people have PhD in signal processing and after peer review have their papers published in AES and such, we have to choice but to at least consider that this is still a concern. :)
Yes, but these PhD's are yet to publish a paper in the JAES that actually shows that jitter IS a real audible problem in modern electronics, as far as I know at least.

Sure John Dawson of ARCAM and Bob Stuart of Meridian claims jitter is a audible problem, they both make money doing so.

/Chuck

Steve Bruzonsky

03-07-09, 11:42 AM

Sure John Dawson of ARCAM and Bob Stuart of Meridian claims jitter is a audible problem, they both make money doing so.

/Chuck

And some spend less money by claiming that there is no such thing as jitter or that jitter is inaudible!!!

'HAAA!

Chuck V

03-07-09, 11:55 AM

And some spend less money by claiming that there is no such thing as jitter or that jitter is inaudible!!!

'HAAA!
Steve, it is a fact that jitter is real, no one is hopefully arguing that's not the case here.

But absolutely no one seems able to actually show that it is a real audible problem in modern electronics.

Why?

/Chuck

RBFC

03-07-09, 12:09 PM

Is that the case in this test though? PCM output on a lossless track and the same gear in the same room seems like it would be a very good method for testing.

Maybe it's just me though...

There was an interesting article in Hi-Fi news (Feb 09) comparing performance of AVR's using the same source.

They are comparing the sound of two different AVRs, using the same source. The AVR's DACs, the preamp section (with various amount of circuitry to travel through), and the amplifier sections all contribute to the sound of the music being played. Jitter cannot be singled out as the sole reason for any sonic differences.

If we were comparing two different BD players using the same chain of electronics to play/display them, then the comparison would be more valid.

Lee

amirm

03-07-09, 01:44 PM

Steve, it is a fact that jitter is real, no one is hopefully arguing that's not the case here.
I think that is how this discussion started. It was said that using a PLL and FIFO on HDMI input eliminated jitter from getting into the audio circuits. So to the extent we agree jitter still exists, we have at least settled the current argument :).

But absolutely no one seems able to actually show that it is a real audible problem in modern electronics.

Why?

/Chuck
Reason is simple. No one can figure out how to conduct the experiment. For starters, what would be the references without jitter? Another device? If so, how would that comparison be valid? Since we don't have jitter-free devices then we would really be comparing two different types of jitter. The fact that one device has less jitter doesn't help us since some types of jitter are far more audible than others.

If you made two versions of the same device, then whatever is different between them could be the reason.

There is a lot of research into simulating jitter. To the extent we understand the nature of the beast better, then there is some hope of being able to model it and then listen to it. I have read the current papers on such experiments but think that we are still way too early to know what to test.

Even if experiments were conducted, it would only be represenative of the device used, and the people in the test. None of which would match you and your setup at home. So the best thing is to test yourself as I suggested. Start simple. See if you can hear any difference as you turn off the front panel and video circuits. If you do, then you must start to believe :).

Art Sonneborn

03-07-09, 01:49 PM

I think that is how this discussion started. It was said that using a PLL and FIFO on HDMI input eliminated jitter from getting into the audio circuits. So to the extent we agree jitter still exists, we have at least settled the current argument :).

Reason is simple. No one can figure out how to conduct the experiment. For starters, what would be the references without jitter? Another device? If so, how would that comparison be valid? Since we don't have jitter-free devices then we would really be comparing two different types of jitter. The fact that one device has less jitter doesn't help us since some types of jitter are far more audible than others.

If you made two versions of the same device, then whatever is different between them could be the reason.

There is a lot of research into simulating jitter. To the extent we understand the nature of the beast better, then there is some hope of being able to model it and then listen to it. I have read the current papers on such experiments but think that we are still way too early to know what to test.

Even if experiments were conducted, it would only be represenative of the device used, and the people in the test. None of which would match you and your setup at home. So the best thing is to test yourself as I suggested. Start simple. See if you can hear any difference as you turn off the front panel and video circuits. If you do, then you must start to believe :).

So if the experiments haven't been done where are the grounds for the high end claims?

It's one of those things which could be claimed to be ameliorated by manufacturer X and it could not be challenged.:(

Art

faberryman

03-07-09, 01:55 PM

Steve Bruzonsky

03-07-09, 01:56 PM

So if the experiments haven't been done where are the grounds for the high end claims?

Art

Vulcans with their unusually shaped ears have much better sense of hearing than humans. On Vulcan no one disputes the audibility of jitter - they can hear it!!! And Vulcans can subjectively tell when a $200 CD transport sounds better than a $2,000 one because the cheaper player does a better job de-jittering. HA!:cool:

amirm

03-07-09, 03:05 PM

Although there are a lot of problems with the testing methodology, I am aware of at least one study that has been done:

http://www.jstage.jst.go.jp/article/ast/26/1/50/_pdf
I am aware of that one in addition to others done diffrently. But they are not what the OP asked about. In this case, they modelled random jitter, and generated two tracks, one without the jitter and one with jitter added to it. Then used the PC as the source and switched between them. Problem I have with their test is that they used random jitter and used a noisey PC as the source. It is unclear to me how they made sure when the source without jitter was used, there was no jitter.

Chuck V

03-07-09, 03:14 PM

Reason is simple. No one can figure out how to conduct the experiment. For starters, what would be the references without jitter? Another device? If so, how would that comparison be valid? Since we don't have jitter-free devices then we would really be comparing two different types of jitter. The fact that one device has less jitter doesn't help us since some types of jitter are far more audible than others.

If you made two versions of the same device, then whatever is different between them could be the reason.

There is a lot of research into simulating jitter. To the extent we understand the nature of the beast better, then there is some hope of being able to model it and then listen to it. I have read the current papers on such experiments but think that we are still way too early to know what to test.

Even if experiments were conducted, it would only be represenative of the device used, and the people in the test. None of which would match you and your setup at home. So the best thing is to test yourself as I suggested. Start simple. See if you can hear any difference as you turn off the front panel and video circuits. If you do, then you must start to believe :).

Well, it can't be that hard to actually put up a test that shows audible differences, that for example Meridian claim exist in there marketing. I mean, they are PhD's...;)

As far as I'm concerned things does not add upp here. No one can put up a valid test method or show measurments related to the audible human threshold, yet manufacturers claim superior audible results, far better then others.

This is not exactly rocket science, test can be made, and published in scientific audio journals for other experts to look at. At lest IF what they are saying is true, that jitter is a audible concern in modern electronics.

It's quite simple. If it can't be shown under controlled tests, it falls under the same category as cable cookers, exotic cable theories and other claimed stuff in my book.

/Chuck

faberryman

03-07-09, 03:26 PM

I am aware of that one in addition to others done differently. But they are not what the OP asked about. In this case, they modeled random jitter, and generated two tracks, one without the jitter and one with jitter added to it. Then used the PC as the source and switched between them. Problem I have with their test is that they used random jitter and used a noisy PC as the source. It is unclear to me how they made sure when the source without jitter was used, there was no jitter.
As I stated, there are problems with their methodology. Since jitter-free sources are not currently available, they could only attempt to show at what level jitter becomes audible. If jitter becomes audible only at (x)ps, then it is inaudible both at (x-1)ps and 0ps. They don't need a jitter free source to support their conclusions.

amirm

03-07-09, 03:28 PM

So if the experiments haven't been done where are the grounds for the high end claims?
Two reasons:

1. We can show mathematically how jitter distorts audio even in small amounts. It is not every day that some crazy audiophile notion can be backed up by math :). Think analog audio cable differences. Or replacing power cables.

The transfer function of a stright line (a linear device) is VERY different if the line has the slightest amount of distortion to it. It doesn't take much at all to create side bands around every frequency in the source.

2. Many people, myself included, can hear something that is only explained by jitter. When I change S/PDIF cables, I hear the difference even with high-end DACs. Hard to imagine anything else being responsible for the difference. Of course, this is not enough to convince many others. But it is good enough for me to base my purchase decisions on it. And come and talk about it here :).
It's one of those things which could be claimed to be ameliorated by manufacturer X and it could not be challenged.:(

Art
It really goes well beyond equipment makers. Studio recroding artists, audiophiles and magazine reviewers say they hear differences such as above. And since the math says it could make a difference, there is plenty of reason to think there is something here worth studying and helping to remove.

Of course, in the context of mass market equipment, no one should really care. And frankly, when watching movies, last thing I worry about is jitter. But for pure enjoyment of music, there is a tiny bit of distortion here.

At the end of the day, the only conclusion you can draw is to have an open mind. There is just too much anecdotal data to say jitter has no impact whatsoever. So when someone says there could be an HDMI for audio with less video noise, I say, "hmmm, maybe that is a good thing." That's all. If I listen to it and hear a difference, then I will advocate it.

Art Sonneborn

03-07-09, 03:37 PM

Two reasons:

1. We can show mathematically how jitter distorts audio even in small amounts. It is not every day that some crazy audiophile notion can be backed up by math :). Think analog audio cable differences. Or replacing power cables.

The transfer function of a stright line (a linear device) is VERY different if the line has the slightest amount of distortion to it. It doesn't take much at all to create side bands around every frequency in the source.

2. Many people, myself included, can hear something that is only explained by jitter. When I change S/PDIF cables, I hear the difference even with high-end DACs. Hard to imagine anything else being responsible for the difference. Of course, this is not enough to convince many others. But it is good enough for me to base my purchase decisions on it. And come and talk about it here :).

It really goes well beyond equipment makers. Studio recroding artists, audiophiles and magazine reviewers say they hear differences such as above. And since the math says it could make a difference, there is plenty of reason to think there is something here worth studying and helping to remove.

Of course, in the context of mass market equipment, no one should really care. And frankly, when watching movies, last thing I worry about is jitter. But for pure enjoyment of music, there is a tiny bit of distortion here.

At the end of the day, the only conclusion you can draw is to have an open mind. There is just too much anecdotal data to say jitter has no impact whatsoever. So when someone says there could be an HDMI for audio with less video noise, I say, "hmmm, maybe that is a good thing." That's all. If I listen to it and hear a difference, then I will advocate it.

Oh well it still sounds like how many angels can sit together on the head of a pin to me but......

amirm

03-07-09, 03:40 PM

If jitter becomes audible only at (x)ps, then it is inaudible both at (x-1)ps and 0ps.
I don't see how you can draw that conclusion. Let's assume the equipment is not capable of resolving the last two bits of 16-bit samples due to jitter of its own. In that case, adding jitter that would be equal or less than 2 bits worth would not be audible because it is destroying what is already been distroyed by other means.

Think of this analogy. Let's say I got a cheap 2 watt amp and drove it at maximum level with 10% THD. Do you think I could hear the difference between jitter at any level and none? Answer is no. That distortion would be lost in the larger one created by the amp.

They don't need a jitter free source to support their conclusions.
Maybe not jitter free but one that for sure had a jitter floor that was well below the audio samples tested.

Mind you, I think it was nice that they did this test and showed that jitter is audible at certain levels. I think that alone is progress as some folks don't even want to consider that it is.

dlarsen

03-07-09, 03:45 PM

Oh well it still sounds like how many angels can sit together on the head of a pin to me but......

Not to mention, the subject of the thread is PQ not AQ. With PQ, there’s really no need for all the theory, rhetoric, and verbiage. You can boil it down to two side-by-side A/B images from the frame buffer. There is either a perceptible difference to the HVS or there isn’t. I believe there is MUCH less hype and snake oil with PQ issues because of this.

Dave

Art Sonneborn

03-07-09, 03:47 PM

Steve Bruzonsky

03-07-09, 04:02 PM

amirm

03-07-09, 04:04 PM

Not to mention, the subject of the thread is PQ not AQ. With PQ, there’s really no need for all the theory, rhetoric, and verbiage. You can boil it down to two side-by-side A/B images from the frame buffer. There is either a perceptible difference to the HVS or there isn’t. I believe there is MUCH less hype and snake oil with PQ issues because of this.

Dave
Yup. You can freeze video but doing so with audio is not so easy. Your ear is also far more sensitive than your eye. It operates in 3-D mode all the time without glasses :D.

Really guys, I don't enjoy defending positions like this. It takes so much time to explain stuff like this and frankly, it doesn't matter at the end of the day as it is not nearly as important as having a decent room and good set of speakers.

As much as I believe in jitter and ability to hear it, I only consider it a factor in critical listening with my Stax headphones. Assuming most of you in this subforum buy good equipment and watch mostly movies, with speakers and not headphones, it is essentially a non-issue.

faberryman

03-07-09, 04:09 PM

There is either a perceptible difference to the HVS or there isn’t.
Perceptible - an equally sticky wicket in both audio and video.

Glimmie

03-07-09, 04:54 PM

Two reasons:

2. Many people, myself included, can hear something that is only explained by jitter. When I change S/PDIF cables, I hear the difference even with high-end DACs. Hard to imagine anything else being responsible for the difference. Of course, this is not enough to convince many others. But it is good enough for me to base my purchase decisions on it. And come and talk about it here :).

This is where it goes into the toilet for me. Are you going to tell us you hear the difference between say 6 feet of Wall Mart RCA cable versus 6 feet of say Belden 1505 which is a precision 75ohm cable in an SPDIF connection?

I can't say what you hear or don't but even the 6 foot Wall Mart cable, while not the proper cable by a long shot, will not influence a PROPERLY DESIGNED SPDIF link. Sure if somethinhg is on the edge it may fail but in most stuff, even the cheap stuff, this will not be detectable by any test equipment. Does the Wall Mart cable induce more jitter due to it's impedance mis-match, perhaps. Does that induced jitter upset the conversion process? Perhaps in theory but I would be seriously challanged to measure it.

All this talk of digital audio jitter? What about video, and Radar? Why isn't this jitter a large issue here?

If we go back to 1980s TV technology we are dealing with digitized analog video. The popular clock frequency was 4x the color subcarrier or 14.318mhz at 8 to 10 bits. Now this chain is no different from a basic CD audio system. Analog video is digitized, processed, converted back to analog, and displayed on an analog CRT. As we know the color subcarriar is highly sensitive to phase shift, 1 degree is visibal to any human. Yet even the early digital processors of the late 70s were able to reconstruct the analog video with residule phase shift down to 0.2%. And that's a 3.58mhz. Now divide that error which was based on the TTL and analog technology of the day down to 44.1khz. Now what is the error?

It was enterily possible in 1980 to get this kind of analog to digital conversion performance on a commercial level. I know we can do magnitudes better today even on a consumer level.

Your jitter theories do have some merit on paper. But you are chasing ghosts. How much time did the removal of one deck chair add to the Titanic staying afloat? How much time did one less file folder prolong the WTC collapse? Well mathmatics can calculate this. Both these examples have an answer. We did in fact reduce the total weight of both these objects so it did make a difference! But does it matter in the net result? This is where many of these jitter theories are going as well.

dlarsen

03-07-09, 04:59 PM

Perceptible - an equally sticky wicket in both audio and video.

I don’t think so. We use A/B images all the time here. If one is honest to himself, he can test and answer… for himself. In the end, it’s one’s own perceptions in ones own environment that matters.

When one reports being able to perceive a delta that no one else can, that person is either truly gifted, delusional, or is trying to sell you something like magic pebbles or a $10K power cord.

Yup. You can freeze video but doing so with audio is not so easy. Your ear is also far more sensitive than your eye. It operates in 3-D mode all the time without glasses

Yes, audio may be more difficult but not impossible. You could capture (losslessly) both audio streams where you claim you can reliably discern a delta. You could then post both streams in an A/B fashion. We could then test the claim (and duplicate and analyze your data) with our own perceptions in our own environment. If one could actually share the real data that supports ones claims, one wouldn’t need so much theory or rhetoric.

When I change S/PDIF cables, I hear the difference even with high-end DACs.

Wow! You can reliably and repeatedly discern an audible delta between two S/PDIF cables? DBT? Just Wow! I’d be interested in seeing your test protocol, methodology, and results. And the list of witnesses. Which brand of S/PDIF cable you prefer?

Why couldn’t you capture the data stream (before and after the S/PDIF cable DUT swap) and provide both data streams that would demonstrate the differences in the data that you claim you can reliably and repeatedly hear?

...it is essentially a non-issue.
Then it's a Ruse? A Red herring?:D You funny.

Dave

amirm

03-07-09, 05:29 PM

Yes, audio may be more difficult but not impossible. You could capture (losslessly) both audio streams where you claim you can reliably discern a delta.
How would I do that? We are talking about analog output of a DAC. If you digitize it, your ADC converter adds jitter and other distortion to it. And then when you play it with your equipment, you add bunch more jitter to it. So nothing meaningful comes out of the experiment.
Wow! You can reliably and repeatedly discern an audible delta between two S/PDIF cables? DBT?
Yes. Some people can. Indeed, the whole research into jitter came about from people who made this observation in 1980s. People laughed at them. I was one of them myself (I couldn't hear any of this stuff until I trained myself in the last few years). Then people went to study things and found out that indeed, changing the cable does impact the receiver/transmitter and changes jitter profile. Read one of the quotes from research paper earlier. The first link I provided also talks about the same.

I guess I am surprised people here have not heard of this phenomena :confused:.
Just Wow! I’d be interested in seeing your test protocol, methodology, and results. And the list of witnesses. Which brand of S/PDIF cable you prefer?
No witnesses. This is not a court of law :). I mentioned how to do the test earlier. Why not try it? BTW, to run it blind, just have someone else connect the cables to your AVR and that way, you don't know which one is which.
Why couldn’t you capture the data stream (before and after the S/PDIF cable DUT swap) and provide both data streams that would demonstrate the differences in the data that you claim you can reliably and repeatedly hear?
The digital data never changes. So capturing it with either cable would show you the same data. It is the effect of cable network with the transmitter and receiver which changes jitter behavior in either source or destination, causing audibility differences once that samples are converted to analog.

FrantzM

03-07-09, 05:38 PM

Hi

Interesting that PQ comes at the forefront. I am not sure everything can be measured adequately, vide the dfferences between a 1-chip and a 3-chip. aside from Lumen most here would agree that there are differences between these; with the most exposed and experienced telling you that the picture in a 3-chipper has a "depth" and sharpness to it not found on 1-chipper... Most people including myself have to be educated into seeing the differences else I am perfectly comfortable with what I saw with the Marantz 12 or 13... then I saw a CX1080 and was taught to see more...

I cannot understand the position that what we are getting from BD is all that BD can produce and that we will not see attempts to extract and results in extracting more .. Have any of you seen the Oppo? Aside from the Elite what are the attempts at the SOTA in bd players ( I would also be quick to dismiss ANY entry from Goldmund, if it exists, we know they will price it in the stratosphere because it is after all their business model)? Have any of you seen one ? Seems that it would be a wise course of action (to audition one) before dismissing the notion of better quality from bd and establishing the PS3 as both the baseline and the ceiling.

dlarsen

03-07-09, 05:39 PM

Yes. Some people can. Indeed, the whole research into jitter came about from people who made this observation in 1980s. People laughed at them. I was one of them myself (I couldn't hear any of this stuff until I trained myself in the last few years). Then people went to study things and found out that indeed, changing the cable does impact the receiver/transmitter and changes jitter profile. Read one of the quotes from research paper earlier. The first link I provided also talks about the same.

I guess I am surprised people here have not heard of this phenomena .

Yes, We’ve heard of it. There’s folk like Mike L, VahallaPC, and others here who claim that they can clearly discern a delta between various cables due to Jitter, EMI, RFI, magnetic waves, gravity, ect…. See my comments about being truly gifted. Or delusional.

The digital data never changes. So capturing it with either cable would show you the same data.
It's all digital data over a digital interface. You say the digital data over those digital cables never changes so no delta can be measured, yet you can hear a delta? Again, you funny.
Why not try it? BTW, to run it blind,….

I have. I’ve changed many a S/PDIF cable in my time. And used cans. No need for me to test blind as I know there was no perceptible delta- even sighted. I know I’m not gifted and I don’t think I’m delusional nor am I selling anything.

…No witnesses. No test protocol, methodology, or resultant data either? Why doesn’t that surprise me.

This is not a court of law

No, it's not. It's a forum with the word SCIENCE in its name.

Dave

amirm

03-07-09, 06:35 PM

Yes, We’ve heard of it. There’s folk like Mike L, VahallaPC, and others here who claim that they can clearly discern a delta between various cables due to Jitter, EMI, RFI, magnetic waves, gravity, ect…. See my comments about being truly gifted. Or delusional.
Well, what is your point of view regarding the researchers in the papers I linked to? Which bucket do they fall in when they mention cable as one of the ways jitter can be induced?

It's all digital data over a digital interface. You say the digital data over those digital cables never changes so no delta can be measured, yet you can hear a delta? Again, you funny.
Please read what I wrote carefully. You asked me if I could capture the *digital* samples. I said yes but they would be the same. We don't hear digital samples. We hear analog audio. That audio comes from a DAC which uses a master clock to convert those digital samples into audio. That DAC is a few circuits away from where the cable plugs in. The problem occurs at the DAC, not at the connection in the back of the machine.

You can however measure the jitter at the DAC master clock. And those measurements do show jitter.

I have. I’ve changed many a S/PDIF cable in my time. And used cans. No need for me to test blind as I know there was no perceptible delta- even sighted. I know I’m not gifted and I don’t think I’m delusional nor am I selling anything.
I doubt that you have run the test as I stated (with two machines so that you could instantly switch between the two). I also didn't ask you to try different "S/PDIF" cables. I asked you to compare a S/PDIF cable with a poorly made one not made for that purpose. I am trying to get you to hear the extreme difference. Once there, then you may be able to hear the subtle. This is how we train people in codec testing by the way. We have them listen to a lot of 32Kbps MP3s before graduating up to hearing differences at 384kbps.

Of course, you may not have the right material, equipement and hearing ability to detect the difference. Which is cool. Most people are in the same boat. But that doesn't invalidate observations from those of us who are not similarly situated.

No, it's not. It's a forum with the word SCIENCE in its name.

Dave
I quote scientific papers. Here are more science for you: http://www.stereophile.com/reference/193jitter/index1.html

Look guys. This is getting a bit tiring. I get it that most of you don't believe in this stuff. That is fine. These discussions are never won. My hope was that folks keep an open mind, read more about the topic, learn what jitter is, how it is measured, what is known about it, and that way, be more educated next time the discussion comes up.

FYI, I used to be one of you guys until I started to educate myself and trained my ears (for codec testing) and next thing you know, I find myself on the other side of the fence. Thank heavens that I did not post my thoughts before that on any forum or I would have a lot of explaining to do :D.

fastl

03-07-09, 07:04 PM

Well, if you want the Prof. Irwin Corey explanation - jitter is phase modulation of the data symbol stream which can be caused numerous mechanisms, not the least of which originates with inexorable sampling clock phase noise. Since phase noise is present in all real (physical) entities, jitter (to some extent) will likewise always be present.

Phase modulation of the audio data stream in the D/A by clock associated jitter will cause modulation sidebands to occur in the output signal, which can be audible under certain circumstances. Those circumstances are difficult to quantify since many parameters come into play, such as the spectral characteristics of the program material, pyschoacoustic masking phenomena and even listener acuity.

So, when someone claims they are hearing jitter effects, one never really knows whether they really are or they are just blowing smoke. Sort of the epistemological problem that audiophiles always face (how you know what it is that you -really- are hearing). Amen.

amirm

03-07-09, 07:15 PM

All this talk of digital audio jitter? What about video, and Radar? Why isn't this jitter a large issue here?
Jitter was an issue in the days we had VGA output from a PC driving LCD monitors. You could see pixel instability. However, today we have digital sources driving digital displays so it is a non issue. The chain is always digital so timing just needs to be close.

Regardless, the two instruments are way, way different. Your ear is incredibly more sophisticated instrument than your eye. We throw away half the color in video and no one seems to blink. Try throwing away half the audio spectrum and hell would break loose.
If we go back to 1980s TV technology we are dealing with digitized analog video. The popular clock frequency was 4x the color subcarrier or 14.318mhz at 8 to 10 bits. Now this chain is no different from a basic CD audio system. Analog video is digitized, processed, converted back to analog, and displayed on an analog CRT. As we know the color subcarriar is highly sensitive to phase shift, 1 degree is visibal to any human. Yet even the early digital processors of the late 70s were able to reconstruct the analog video with residule phase shift down to 0.2%. And that's a 3.58mhz. Now divide that error which was based on the TTL and analog technology of the day down to 44.1khz. Now what is the error?
That is not how we measure the impact though. How much damage jitter does depends on the frequency and bit depth. In case of audio, we have bit depths of 16, 20 and 24 bits. Even in case of 16 bits, we have 96 db of dynamic range. This means that any distortion products must be -96 db down or they will be lower the effective resolution of the system below that of 16 bits. Translated into (sinusoidal) jitter, this amounts to an amazing, 250 trillionth of a second (250 picoseconds)! And again, this is only for 16 bit and 20Khz. Use 24-bit and 96Khz and you are in much tighter territory.

Expanding on above, sinusoidal jitter FM modulates the original signal, creating sidebands on each side of the original signal. If the amplitude of these sidebands is more than 1-bit worth of sample size, then we have just lowered the DAC accuracy by equiv amount.
Your jitter theories do have some merit on paper. But you are chasing ghosts. How much time did the removal of one deck chair add to the Titanic staying afloat? How much time did one less file folder prolong the WTC collapse? Well mathmatics can calculate this. Both these examples have an answer. We did in fact reduce the total weight of both these objects so it did make a difference! But does it matter in the net result? This is where many of these jitter theories are going as well.
Fair point. I hope we can agree on two additions to your list:

1. Not everybody has the same hearing ability. And that a select few are better that most of the population.

2. We don't know the relative levels of forces you describe. I know if I remove a chair from my 10 foot aluminum boat it makes a huge difference :). So unless you can prove your analogy is more correct than mine, we are stuck. See the math above on how little it takes to reduce resolution below 16 bits.

dlarsen

03-07-09, 11:12 PM

So, when someone claims they are hearing jitter effects, one never really knows whether they really are or they are just blowing smoke. Certainly not without a method to test such a claim. Science has methods to test such claims and identify placebo and delusion. It involves statistics, probability, and many, many test runs to achieve a statistically valid sample size from which conclusions can be made. And yes, witnesses.

Well, what is your point of view regarding the researchers in the papers I linked to? Which bucket do they fall in when they mention cable as one of the ways jitter can be induced? At least one of your references falls into the “Trying to sell something” bucket IMO. If I’ve designed, developed and market devices that measure clock phase jitter, I may have a bias that is independent of my actual measurable perceptions. I almost get the sense that you’re trying to sell something too. Don’t tell me… you’re now developing a new jitter reduction technology that will be coming to market soon? :D

Stereophile? Aren’t they the ones who also publish/endorse Jason Sinius, the dude that swears by $10K cryogenically cooled power cords, magic pebbles and disk mats? And swears to perceive dramatic differences in video with them as well? Yet fails statistically valid DBT? And can cure disease by whistling? :D

I doubt that you have run the test as I stated (with two machines so that you could instantly switch between the two). I also didn't ask you to try different "S/PDIF" cables. I asked you to compare a S/PDIF cable with a poorly made one not made for that purpose.

What? You didn’t ask me to use two different identical machines. You said: …to run it blind, just have someone else connect the cables to your AVR and that way, you don't know which one is which.

I also didn't ask you to try different "S/PDIF" cables. I asked you to compare a S/PDIF cable with a poorly made one not made for that purpose.
Again- What??? That’s not what you said. You said you could reliably hear the difference between two S/PDIF cables. That claim is what brought me into this thread. I thought that claim was incredulous. You never said anything about a “poorly made S/PDIF not made for S/PDIF purpose”? WTF is that? A coat hanger wire?

Of course, you may not have the right material, equipement and hearing ability to detect the difference. Which is cool. Yea, I know. I must just be one of the unwashed, un-enlightend, un-educated, not a good enough system slobs. I’ve heard that argument before too. Untestable. Science generally eschews untestable theories.

As I said, to me, you’re either very gifted, delusional, or trying to sell something. I’m full up on crazy presently, so I’m not in your market for more.

You summed it up nicely earlier:
...it is essentially a non-issue.

Dave

amirm

03-08-09, 12:04 AM

At least one of your references falls into the “Trying to sell something” bucket IMO. If I’ve designed, developed and market devices that measure clock phase jitter, I may have a bias that is independent of my actual measurable perceptions. I almost get the sense that you’re trying to sell something too. Don’t tell me… you’re now developing a new jitter reduction technology that will be coming to market soon? :D
I am not trying to sell you anything other than having an open mind ;). That seems to be a hard sell so I should go and find some other business :D.
Stereophile? Aren’t they the ones who also publish/endorse Jason Sinius, the dude that swears by $10K cryogenically cooled power cords, magic pebbles and disk mats?
I am not selling you a subscription to Stereophile. I provided an article that was clearly written, was based on science and had pretty graphs that communicate the message better than my words. I promise you there was nothing in there about power cables.

Did you read the article? If so, what objection do you have to the information in there? You preach science yet I have not yet heard back what your objection is with the data presented. What is the jitter spec for the equipment you own?
Again- What??? That’s not what you said. You said you could reliably hear the difference between two S/PDIF cables. You never said anything to me about a “poorly made S/PDIF not made for S/PDIF purpose”? WTF is that? A coat hanger wire?
I said *I* could hear the difference between two S/PDIF cables. Not that you can. For you, I presented an easier case. And I mentioned in my post why. That is, how we train people to hear things like quantization noise and jitter. That is how I learned to hear jitter. As the father said to Jodi Foster’s character in movie Contact, “Small moves, Ellie, small moves…”
Yea, I know. I must just be one of the unwashed, un-enlightend, un-educated, not a good enough system slobs. I’ve heard that argument before too. Untestable. Science generally eschews untestable theories.
I gave you three reasons why you couldn't hear the difference:

1. You don't have the right equipment.

2. You don't have the right source material.

3. You don't have the hearing ability.

You seem to have focused mostly on #3. I gave you two chances to not accuse yourself of all those things yet you didn't see it ;) :). Do you know what material you should have used? How about equipment?
As I said, to me, you’re either very gifted, delusional, or trying to sell something. I’m full up on crazy presently, so I’m not in your market for more.
OK, since you keep repeating this line over and over and over again, I take “gifted” as my choice. :D Can we now move on without repeating this line again? I get the back-handed compliment. I really do. You summed it up nicely earlier:
I did, didn't I? But let me expand since the meaning seems to have been lost. I don't advocate 90% of what audiophiles chase. I chuckle at the equipment reviews in Absolute Sound as much as the next guy as they read like wine reviews than electronics. But I do allow for 10% to be true because both the science and my own listening experiences agree with it. If you were in my shoes, I assume you would do the same. Many of you here have bought $20,000 projectors because you accept the science behind their expensive designs and what your eyes tell you. You want to know what words the general public would use do describe those purchases? Delusional would be too good of a word, I promise you!

dlarsen

03-08-09, 12:36 AM

Did you read the article? If so, what objection do you have to the information in there? You preach science yet I have not yet heard back what your objection is with the data presented.

Yes, I scanned several of your references. Most of them seem to make little to no comment on the ability of the human auditory system to discern a jitter based delta or to testing of that claim. You clearly do and did. I didn’t take exception or express an objection to your references or the science in them. I took exception of YOUR auditory claims and YOUR seeming lack of science in applying a proper DBT to YOUR claim of being able to reliably and repeatedly discern an auditory delta between S/PDIF cables. I asked for your test protocol and methodology and you were mum. How many DBT tests did you run and what were the result for each test? 32 for 32? 100% or 2 for 3 66%? Big difference if you're testing for placebo or delusion.

What is the jitter spec for the equipment you own? I have no idea. It’s windows HTPC based. Probably uses MS Kmixer :D Was your group responsible for that? :D

I gave you three reasons why you couldn't hear the difference:
You seem to ignore the most obvious and direct possibility and reason. Hoofprints most likely indicate the presence of horses, not zebras. Occam. And you lecture me as a father to his daughter about taking small steps. :D

#4- There is no perceptible difference.

That seems to be a hard sell so I should go and find some other business

Yea, I imagine selling the purported audible advantage of jitter reduction in A/V may be tough. Especially if it's so hard to test, confirm and demonstrate or otherwise prove in an audible or visual manner. Good luck with that. They sold the BTB/WTW/banding hype/myth thing to many here so I guess most anything is possible. :D

Dave

amirm

03-08-09, 01:25 AM

I have no idea. It’s windows HTPC based. Probably uses MS Kmixer :D Was your group responsible for that? :D
No. My group was responsible for the total redesign in Vista. You can read more about it here: http://www.avsforum.com/avs-vb/showthread.php?t=713073

If you are using K-mixer, then you have tons more problems than jitter. I think cassette tapes sounded better than the algorithms in there for volume and mixing :).

Are you getting analog output out of the PC then?

dlarsen

03-08-09, 03:01 AM

No. My group was responsible for the total redesign in Vista. You can read more about it here: http://www.avsforum.com/avs-vb/showthread.php?t=713073

If you are using K-mixer, then you have tons more problems than jitter. I think cassette tapes sounded better than the algorithms in there for volume and mixing :).

Are you getting analog output out of the PC then?
Well I'm not running Vista on the HTPC and I can run 5.1 via analog or S/PDIF. I do both.

But really, this is not about my equipment or my hearing abilities or how I interface, decode or mix. I'm not the one making an extraordinary claim that I can reliably and repeatedly hear a difference between two S/PDIF cables. You are.

I find it interesting which of my comments and questions you choose to respond to and which ones you choose to ignore. How many DBT did you conduct and what were the totals? I think we know how this story ends.

Peace out.

Dave

amirm

03-08-09, 03:09 AM

Well I'm not running Vista on the HTPC and I can run 5.1 via analog or S/PDIF. I do both.
I supsect then you are suffering from more jitter than any difference between S/PDIF cables.

But really, this is not about my equipment or my hearing abilities or how I interface, decode or mix. I'm not the one making an extraordinary claim that I can reliably and repeatedly hear a difference between two S/PDIF cables. You are.
Well no. You said you had tested the same and couldn't hear the difference. So your methodology for testing is fair game. You shouldn't have offered your situation as a counter to mine :).

I find it interesting which of my comments and questions you choose to respond to and which ones you choose to ignore. I think we know how this story ends.
No, it is late and I didn't want to tangle with you on the rest of the points....

Chuck V

03-08-09, 03:17 AM

I chuckle at the equipment reviews in Absolute Sound as much as the next guy as they read like wine reviews than electronics. But I do allow for 10% to be true because both the science and my own listening experiences agree with it.

But in all fairness this is not true in this jitter discussion, science has NOT shown jitter to be a audible facor in any peer reviewed journals. And this is the problem for most, it certanly is for me. It has not been shown.

I have read lots and lots about jitter, even your thread about it Amir. :) And even if i really appreciate the knowlegde you put in I'm not convinced this is a issue at all.

/Chuck

dlarsen

03-08-09, 03:28 AM

So your methodology for testing is fair game. You shouldn't have offered your situation as a counter to mine

But you haven’t offered ANY methodology, test, data, or results in support of YOUR claim that YOU can repeatedly and reliably discern an audible delta in jitter between S/PDIF cables. I’m not making a claim. The default hypothesis is the null. You totally ignored it as even a possibility. You can’t prove a negative.

It seems you’re trying to flip this around into the- “Well- prove to me there isn’t a god” then. That is unreasonable, so there’s no sense in trying to reason with it.

Dave

Dizzman

03-08-09, 04:07 AM

there have been numerous far reaching debates here about cables differences. and every time it comes down to one side or the other.

Either A
"Go Ahead... show me one... just one published study where an AB test has been done with even moderate controls in place where ANYBODY has EVER picked out the difference in the sonic experience between two cables of moderate construction that do not have filters or networks in place"

And to the best of my knowledge... nobody ever has. heck, james randi will pay you a million dollars if you can do it.

And the other side is B.
(and i thank you for summarizing.)
1. You don't have the right equipment.

2. You don't have the right source material.

3. You don't have the hearing ability.

Which is short for saying that...
"I have not done an AB test with even moderate controls in place"
And for the record, every time a test gets done, none of those three are valid.

Without a true blind test in place, then what you are saying is merely observational. and if there is one thing that cannot be trusted... it is the human powers of observation.

And what i personally always feel is that if and i do emphasize IF you feel that there is a difference between two cables, then there is test gear that can record the output of the speakers at the listening position and compare the two passages and be able to tell if there is a difference with a far far greater resolution than any human. not saying it can tell us what it is hearing, or if one is better, nothing like that. only if there is a difference.

mark haflich

03-08-09, 07:45 AM

Its the same old arguments over and over and over again.

With video PQ between two projectors, its now put it up on a screen side by side, treating the screen as two screens with each projector centered on its half screen. With sources its . . . .

Suppose one looks better to you. Is it acccurate. But it looks better to me. I can see the difference. I can not see a difference. But wait, I now change the screen and I can clearly see a difference between two projectors which I could not see before because of pixel bleed. On and on and on. I can measure an on off difference between projectors of say 1271. Whoopee. Buy the one thats 1271 higher. There is so much to perceived video quality that no measurements exist for. Or maybe there is. I just picked up a new MTF meter at the Radio Shack store down the street for $49 and I will post the results after I complete my screen gain uniformity measurements using a Minolta LS110 with a calibrated 2 inch Spectralon disk all powered by a regulated power supply. A Gardner Tri gloss meter is being used to measure screen gloss. PM me if you want the detailed test methodology. The methodology will eliminate any uniformity issues caused by the projector. Maybe I will start a new thread on the methodology. The results will be critically important given that I watch my sports in the middle viewing position and obviously will chuck my new screen if the gain uniformity varies from the center by more than what 5 percent, 10 percent, 15 percent.

fastl

03-08-09, 08:15 AM

...Suppose one looks better to you. Is it accurate. But it looks better to me....

Same with loudspeakers, which is why I tend to stay out of those "discussions". However, this is Audio Video SCIENCE, where things of a technical nature related to audio and video tend to be discussed. It would probably be more productive with technical topics, like vertical interval jitter, if the subjectivist viewpoint was less accentuated.

mark haflich

03-08-09, 08:40 AM

Science continuously evolves. Most scientists here are actually engineers of one sort or another. Quite a difference between the two. Engineers, I was one once, tend to be locked into what they were taught. Flat earthers. Small limited closed minds. Scientists tend to explore, knowing that they do not know and knowing that yet unknown measurable datum exist to destroy the theory that at this time fits present measurements.

CINERAMAX

03-08-09, 08:44 AM

LOL,

Welcome Back Mark.

Art Sonneborn

03-08-09, 10:05 AM

I just picked up a new MFT meter at the Radio Shack store down the street for $49 and I will post the results after I complete my screen gain uniformity measurements using a Minolta LS110 with a calibrated 2 inch Spectralon disk all powered by a regulated power supply.

:eek:I can't believe it. I wonder if Radio Shack will honor the price drop on my unit. I paid over a hundred dollars just a week ago.

Art

amirm

03-08-09, 12:27 PM

there have been numerous far reaching debates here about cables differences. and every time it comes down to one side or the other.
What you state is very true. But I am hoping that people through these discussions understand each other a little more. And that occurs with information, not my opinion is more right than yours. Your post is very kosher but others calling the other side Delusional and such, just shows we can’t yet communicate.
"Go Ahead... show me one... just one published study where an AB test has been done with even moderate controls in place where ANYBODY has EVER picked out the difference in the sonic experience between two cables of moderate construction that do not have filters or networks in place"

And to the best of my knowledge... nobody ever has. heck, james randi will pay you a million dollars if you can do it.
First let's be clear. The topic is digital audio and transmission of such. We have not gotten into analog interconnects, power cords, or speaker cables. In those areas, it is hard to come up with measurements or what science would explain the differences. In the case of digital though, measurement (at least for traditional audio interconnects) is easy, documented and analyzed by both engineers and reviewers.

And people are conducting listening tests. It is just that it is hard to simulate real life. Here is an example from a research posted earlier: http://www.wolfsonmicro.com/uploads/documents/en/Specifying%20Jitter%20Performance.pdf

“Detection threshold for distortions due to time jitter was measured in a 2 alternative forced choice paradigm with switching sounds. Music signals with random jitter were simulated on the digital domain. The size of jitter was arbitrary controlled so that the detection threshold could be estimated. Professional audio engineers, sound engineers, audio critics and semi-professional musicians participated as listeners. The listeners were allowed to use their own listening environments and their favorite sound materials. It was shown that the detection threshold for random jitter was several hundreds ns for well-trained listeners under their preferable listening conditions.

When the jitter size was 2 ms (r.m.s.), all listeners scored more than 75% correct. About 25% of the listeners detected jitter when its size was 500 ns. When it was 250 ns, however, no listener could discriminate the sounds.”

The article goes on to say that they think average CE equipment has much less jitter so this is a non-issue. However they don’t provide any detail on that. And per my earlier note, they used random jitter which is usually far less audible because it is not correlated with the input samples and used a PC as the source which may have swamped the jitter they were injecting. We also don’t know the quality of the material they used (i.e. if the content really did have meaningful information in the low order bit of 16-bit word).

Putting all that aside, as you see, unlike the other type of cables you proposed, we do have data on jitter being audible at some level. That’s why I ask people if they know what jitter their equipment has and I hear “no.” Then how do you know you don’t fall in the above bucket? And bringing us full circle to the original topic, I have yet to see any measurements of audio jitter over an HDIM output of a device. How much jitter does your blu-ray player put out?

Besides, what ultimately matters is your own ears. I have provided a way for people to conduct a simple exercise. How come no one is interested enough to try it? After all, even if I had shown you a study that said these 10 people heard a difference at 0.01 picoseconds, it wouldn’t matter because their ear may be different than yours.

Here is a simpler exercise. Take a source which has both Toslink optical out and S/PDIF. Put your favorite (non-rock) CD or DVD-A in there and then switch back and forth. I think you be surprised to hear that they sound different. I have done this test and added AES/EBU link to it which is the balanced version of S/PDIF. And you know what? All three sound different. Why might we have two versions of S/PDIF and why the pros don’t use regular S/PDIF? Because a balanced link tends to not create ground loops which also impacts jitter.
Which is short for saying that...
"I have not done an AB test with even moderate controls in place"
And for the record, every time a test gets done, none of those three are valid.
Well I have done my testing double-blind with the setup I mentioned and reached the results I have reported. As far as I can tell, no one seems to have tested what I have suggested. Until people do, then I am the only one with the data :).

BTW, you cannot have a reference here. Because jitter free device does not exist. All you can tell is that the two setups sound different. But that is enough to dismiss the myth that “digital is digital.” After all, if I am not getting audio glitches/data loss then what explains the different sound?
Without a true blind test in place, then what you are saying is merely observational. and if there is one thing that cannot be trusted... it is the human powers of observation.
It is. And if I were an average Joe you could make all of those assumptions. But not in this case. For a decade we developed audio compression algorithms at my last job so performing double bind tests and participating in them was matter of course. I am also fully aware of power of the mind in both directions: have it think there was a difference when there was none. And having the difference be there that others hear, that you cannot. I also know what limitations you have to remove first for the test to be valid (hence my suggestion to use headphones, turn off video, etc.).

I am also aware of where blind tests go wrong. You cannot play a 3 minute song. Stop the machine and switch cables. Play again and expect to be blown away by the difference. Your brain does not have that kind of memory to remember things. Research shows that you must stay within 4 seconds. So it is essential that you have a setup that lets you do immediate switching. I confess that I will fail these tests if you conduct the experiments sequentially.

In addition, I would have definitely failed these tests had I not trained my ears. My first CD player was from Techniques/Panasonic and had a single DAC which it switched between left and right channels. I kid you not! I thought that sounded every bit as good as the Meridian modified Philips CD player my "crazy" audiophile friend had bought. After all, digital was digital.
And what i personally always feel is that if and i do emphasize IF you feel that there is a difference between two cables, then there is test gear that can record the output of the speakers at the listening position and compare the two passages and be able to tell if there is a difference with a far far greater resolution than any human. not saying it can tell us what it is hearing, or if one is better, nothing like that. only if there is a difference.
You cannot do that unfortunately. Because you have to use something to digitize the audio. That device in turn adds jitter and other distortion. Then when you play the recorded material, you add more jitter to it yet again.

I wish you had heard the difference I have. It is so small as to not be capturable that way. And certainly not with speakers playing. So hopefully there is no confusion in thinking there is a huge difference (at least when speaking of well designed equipment).

No doubt, the above provides an "out" in all of these discussions as you noted. That can't be helped. Heisenberg principal is alive and well here (that the experiment impacts the outcome). But I believe that with time more will be learned about what type of jitter is bad and how to deal with it.

So please keep an open mind. Allow yourself to truly hear the other side. Allow your ears to develop their acuity. It opens a wonderful new vista for you that isn’t there otherwise. Then again, maybe you don’t want to do that. When someone refuses to eat Uni (sea urchin roe), I tell them they are lucky because it is one of the most expensive types of sushi there is! Sadly for me, both I and my three sons eat and enjoy it :).

Dizzman

03-08-09, 01:59 PM

if i measure the SPL waveform at the listening position then this is a different and seperate aspect. it is completely isolated from the playback gear. and if we measure with sufficient resolution, then we can be far past the threshold of human hearing.

so now an isolated and secondary system records the two playbacks. IF and it is a large IF there was any difference at all (let alone in the audible range) then we would be able to detect it.

I am not talking about trying to record jitter somewhere. I am talking about recording the audio coming out of a speaker system. the jitter in that system is irrelevant in any aspect other than if it CHANGES the sound in a real circumstance of music playback.

I wish you had heard the difference I have. It is so small as to not be capturable that way. And certainly not with speakers playing. So hopefully there is no confusion in thinking there is a huge difference (at least when speaking of well designed equipment).

Well, if it can be heard... by ANYBODY... then test gear can record it. or i should say can record the difference.

Besides, if there really was a difference in cables... then somebody somewhere would be marketing based upon it and not by making things up as most of them do.

Glimmie

03-08-09, 02:05 PM

Why might we have two versions of S/PDIF and why the pros don’t use regular S/PDIF? Because a balanced link tends to not create ground loops which also impacts jitter.

Not exactly true, Ever hear if AES3? That is a 75ohm unbalanced version of AES-1992 which is the balanced version. The only difference between AES3 and SPDIF are the channel status bits. AES3 has channel ID. SPDIF used the same bit field for copy protection in the long since forgotten consumer DAT machines. In just about all applications they are interchangable and I have done it many times.

AES3 was deveolped for the television industry for many reasons, mainly the mechanical connectivity isuess and the difficulty in using TRS patch bays at 3mhz. I have seen claims that AES3 actually performs better than the balanced AES-1992 over long distances. The reason is the main problem in unbalanced transmission is 50/60hz noise. The AES stream is mostly immune to that as it is so far down in the spectrum.

Just about any large TV or Radio plant being built today is using 75ohm AES3 and not the balanced AES-1992. It works just as well.

dlarsen

03-08-09, 02:25 PM

Your post is very kosher but others calling the other side Delusional and such, just shows we can’t yet communicate.

But saying one side is full of closed-minded, flatlander, unenlightened hicks, or talking down like a father to his daughter (baby steps, Ellie) is kosher and furthers discussions? Besides you choose the ‘gifted’ label. :D

Until people do, then I am the only one with the data .

What data? How many DBT did you conduct? What was the total? 32 for 32? I've STILL not seen you answer this.

Heisenberg principal is alive and well here

Oh my, so now we’ve arrived at that? The claim can never be tested because of Heisenberg uncertainty? It's a quantum phenomena? Where was Heisenberg when you conducted all of your DBT? If you 'pass' a DBT then it was a good test but if you fail it's because of Heisenberg or the test isn't fair? That's very selective for you. You only count the positive results and dismiss the negative? This sounds alot like many of the other DBT that have been conducted here. Folk claim to pass them all day long untill there are some controls put in place and a proper score is kept. Then they fail. You already said you didn’t have any witnesses for all of the DBT you conducted. Your results are suspect and hardly proper without witnesses, methodology, and resultant data. We should all just have an open mind and trust on faith alone? Father knows best?

Dave

amirm

03-08-09, 02:44 PM

What data? How many DBT did you conduct? What was the total? 32 for 32? I've STILL not seen you answer this.
I have conducted tests half a dozen times using different configurations. The sample size is always one: me!
Oh my, so now we’ve arrived at that? The claim can never be tested because of Heisenberg uncertainty?
Not never. People eventually did show that earth was round. And that Einstein was right in that time does vary in the face of speed. There is good work being done here and I am confident we will keep making better equipment and learning more how to test them. For now though, I am dismayed that we are totally in the dark on HDMI audio.
Where was Heisenberg when you conducted all of your DBT? If you 'pass' a DBT then it was a good test but if you fail it's because of Heisenberg or the test isn't fair?
Sorry but what does Heisenberg have to do with that?
That's very selective for you. You only count the positive results and ignore the negative?
You seem to be selective just the same. I just quoted a study where jitter was heard. What is your reaction to that? You ask for data and when I present it as solid as it gets, there is nary a mention.
Folk claim to pass them all day long up and untill there are some controls put in place and a proper score is kept. Then they fail. You already said you didn’t have any witnesses for all of the DBT you conducted. Your results are suspect and hardly proper without witnesses, methodology, and resultant data.
Well, I presented you as the ultimate witness. Do your own test. Don’t keep talking and typing. Do some testing. What is there to be afraid of?

Note that I have not presented my finding beyond the value of the results. A sample size of one. From an experienced listener who expected to hear NO difference but did. And someone who used to be just like you, a non-believer. And a person who is not afraid to admit when he is fooled by his ears. All together, this doesn’t prove anything but it is far different picture than the random internet poster claiming the same and defending expensive audio purchases. So please put aside standard talking points. I know them inside and out.

gamelover360

03-08-09, 02:44 PM

This is my first post in this sub forum. I started in the PS3/XBox 360 forum years ago, then ventured into the display device forums, then into the speaker forums, then receivers, amps, then etc. etc.

I love AVS forum and Home Theater. Mainly due to the fact that I love to research, shop, buy AV, then tweak and optimize, and UPGRADE:). Also, I love movies, and the fact that they can be brought to your home in today's quality is awesome!

I post here because you are discussing something very relevant to me now. I currently have a nice setup in the family room....but have come into some money and now can do a MAN room upstairs...aka my very own home theater room! The only caveat is that the couch must fold out to a bed for a guest if we have company.....small sacrifice:D

I am so excited! I can get almost whatever I want, within reason. I actually won't be getting any one component that costs $20,000, but my budget is a total of around $40,000. but about $10,000 needs to be saved for Blu rays, furniture, DIY acoustic treatment, and rainy day money. So in actuality it is $30,000. maybe small change for many in this forum, but a once in a lifetime opportunity for me.

I hope it is OK, even though I won't be spending $20,000 on any one device...and I post here because most of you have forgotten more about AV than I will ever know. I respect your opinions, and some of you are industry professionals, so it is an honor to get your input for me.

After visiting some of the Hi Fi salon shops and looking at high end stuff (in my money terms anyway), I started to have my BS detector set off. I have read a lot on AV, and have picked lots of broad knowledge...without becoming an expert in any one thing.

Questions:

******All I care about is Blu ray playback.

1) I have read reviews (could be influenced by sponsors) that have said BR player X is better Blu Ray PQ than the PS3 (my current BR player). Does anyone agree or disagree?

2) I have heard "audiophiles" claim that bitstreaming HD audio is superior sound quality than having the Br player decode. Does anyone agree or disagree? (Because the PS3 can only decode not bistream the HD codecs)

3) I am now leaning towards the Klipsch THX Ultra 2 7.2 speaker package (http://www.hembioconsult.se/db/db.cgi?id=2469&template_file=index_link.html&template_link=db_vara.html). They are 8 ohm speakers. They also have a separate amp they come with. How many watts should my receiver be rated at for continuous 7 channel output to not limit my speakers?

4) I know that THX Ultra 2 certification is just a standard that a company can decide to pay to attempt to get. But I am still stuck on feeling my receiver should be THX Ultra 2 certified to match my speakers. I know it may be silly, but I have always wanted to be able to say "yes" when my receiver asks if my speakers are THX. :p Is this just really ridiculous?

5) If the receiver is giving me the proper watts, will certain receivers give me better sound quality? I am kinda between the mid range Denon (http://www.hifiklubben.se/produkter/hemmabio/receiver/denon_avr-3808a_hemmabioreceiver_svart.htm) and the top line Denon (http://www.hifiklubben.se/produkter/hemmabio/foerstaerkare/denon_avc-a1hda_hemmabiofoerstaerkare_premium_silver.htm). I have no need for home networking or two channel music features...just Hd audio in Blu rays. But I do need a room correction system (MCAAC, Audyssey, etc.)

Thanks in advance for any input. I have decided that I want my money to go into the display and the speakers...and only spend what I need to on the BR player and the receiver to get the most out of the other two.

amirm

03-08-09, 03:01 PM

if i measure the SPL waveform at the listening position then this is a different and seperate aspect. it is completely isolated from the playback gear. and if we measure with sufficient resolution, then we can be far past the threshold of human hearing.
You present a scenario which can only support one side of the argument :). Where would I buy a system which records and playsback audio past the threshold of human hearing? I have looked at any many audio equipment ads and they never claim to be better than the human ear. If there was such a equipment, then we would all buy that and it would be end of the discussion.

I assume you mean a digital recording system and not analog. Correct? If so, we would have to use an A/D converter to get to digital samples. And a D/A converter to convert them back to audio.

Both the A/D and D/A in the above sample would add their own jitter characteristics to the recordings and playback. So in that sense, they can easily swamp the jitter that may be in one or the other recording. This is assuming the A/D to D/A path is perfect in every other way which we know is not the case.

So no, we can't perform that test in this scenario.

IF and it is a large IF there was any difference at all (let alone in the audible range) then we would be able to detect it.
First, it is not a large difference. I have said that a number of times. If the difference is small, who is to say it doesn't get lost in another chain of analog to digital and back to analog again?

I am not talking about trying to record jitter somewhere. I am talking about recording the audio coming out of a speaker system. the jitter in that system is irrelevant in any aspect other than if it CHANGES the sound in a real circumstance of music playback.
Well unless your recording is free of jitter, we can't use it to test jitter in the DUT.

Well, if it can be heard... by ANYBODY... then test gear can record it. or i should say can record the difference.
Nope. You assume a perfect recording machine. Such a machine doesn't exist.

Besides, if there really was a difference in cables... then somebody somewhere would be marketing based upon it and not by making things up as most of them do.
http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10236&cs_id=1023601&p_id=2743&seq=1&format=2

"This cable allows jitter-free transfer of digital audio signals."

http://www.providencecable.com/products.asp?cid=5786969
"Digital S/PDIF Cable for Maximum Sound with Minimal Noise. The digital data may be a precise set of zeroes and ones, but it takes a high-quality digital coax cable to reduce jitter, maximize data transfer and reject noise from outboard DACs, DAT machines or monitors. "

http://www.monstercable.com/productdisplay.asp?pin=3864
"Enhanced Jitter Reduction for Smoother, Natural Digital Audio
For truly dramatic home theater, digital audio is just as important as digital video. Unfortunately, jitter can be a serious problem in digital audio cables. This clock-signal error causes digital bits to be converted into analog waveforms with inaccurate phasing. This can distort the sound of your favorite movies and music. Ordinary coaxial audio cables with inferior construction can actually increase clock jitter. For the most accurate transmission of the digital bitstream and total enjoyment of your movies and music, choose the cable audiophiles trust: M1000DCX Digital Coaxial."

http://www.abccables.com/90-2681.html
"This cable connect dvd players to audio receivers, Sattelite boxes and cable boxes to audio receivers, computer audio equipment, and any other equipment that supports Coax(S/Pdif) interface interconnect. This cable allows jitter-free transfer of digital audio signals. "

http://www.purenote.com/alluvion_rca_digital_cable.htm
"Sonic Impression: Our Alluvion RCA digital cable is impedance matched to all 75 Ohm digital interfaces for jitter-free signal transmission. This renders a noiseless, black background and a precisely focused soundstage with lifelike musical clarity."

This was all from the first search page :).

dlarsen

03-08-09, 03:10 PM

Note that I have not presented my finding beyond the value of the results. A sample size of one.

6 tests with one lone observer. I did note that. A sample size of one is not a good sample size nor is 6 tests nearly statistically valid. I can get a coin toss to come up heads 6 times in a row.

Dave

faberryman

03-08-09, 03:11 PM

Where would I buy a system which records and playsback audio past the threshold of human hearing? I have looked at any many audio equipment ads and they never claim to be better than the human ear. If there was such a equipment, then we would all buy that and it would be end of the discussion.
Actually, I think a lot of audio equipment is better than human hearing. I for one know that my hearing is flat from 20Hz to 20KHz.

Dizzman

03-08-09, 03:12 PM

http://www.eaw.com/products/software/EAWSmaart/

with any number of excellent USB ADC's and a good mike such as a neumann or the like you will easily surpass the resolution of human hearing.

i am not proposing testing for jitter. i am proposing whether the jitter you proclaim is audible can be detected in the audible signal. and as far as your claim that the difference is tiny... this software (and it does have a 30 day trial available) is more than up to the task of finding that difference.

dlarsen

03-08-09, 03:14 PM

http://www.monoprice.com/products/pr...seq=1&format=2

"This cable allows jitter-free transfer of digital audio signals."

http://www.providencecable.com/products.asp?cid=5786969
"Digital S/PDIF Cable for Maximum Sound with Minimal Noise. The digital data may be a precise set of zeroes and ones, but it takes a high-quality digital coax cable to reduce jitter, maximize data transfer and reject noise from outboard DACs, DAT machines or monitors. "

http://www.monstercable.com/productdisplay.asp?pin=3864
"Enhanced Jitter Reduction for Smoother, Natural Digital Audio
For truly dramatic home theater, digital audio is just as important as digital video. Unfortunately, jitter can be a serious problem in digital audio cables. This clock-signal error causes digital bits to be converted into analog waveforms with inaccurate phasing. This can distort the sound of your favorite movies and music. Ordinary coaxial audio cables with inferior construction can actually increase clock jitter. For the most accurate transmission of the digital bitstream and total enjoyment of your movies and music, choose the cable audiophiles trust: M1000DCX Digital Coaxial."

http://www.abccables.com/90-2681.html
"This cable connect dvd players to audio receivers, Sattelite boxes and cable boxes to audio receivers, computer audio equipment, and any other equipment that supports Coax(S/Pdif) interface interconnect. This cable allows jitter-free transfer of digital audio signals. "

http://www.purenote.com/alluvion_rca_digital_cable.htm
"Sonic Impression: Our Alluvion RCA digital cable is impedance matched to all 75 Ohm digital interfaces for jitter-free signal transmission. This renders a noiseless, black background and a precisely focused soundstage with lifelike musical clarity."

This was all from the first search page .

Those would certainly fall into the ‘Trying to sell you something’ bucket, Eh? Besides, you note that jitter-free doesn't exist. Yet there are all the claims of jitter-free transmission.

Dave

amirm

03-08-09, 03:28 PM

http://www.eaw.com/products/software/EAWSmaart/
That is a link to software, not hardware.

with any number of excellent USB ADC's and a good mike such as a neumann or the like you will easily surpass the resolution of human hearing.
Well, where is the claim then? Note that I am not talking about "resolution" but the device being perfect in every other way.

i am not proposing testing for jitter. i am proposing whether the jitter you proclaim is audible can be detected in the audible signal. and as far as your claim that the difference is tiny... this software (and it does have a 30 day trial available) is more than up to the task of finding that difference.
The software can. My Audio Precision analyzer ($20K device) also measures and shows jitter. But they go on and admit that the device itself has X amount of jitter so it cannot be used to measure jitter below that.

amirm

03-08-09, 03:31 PM

Those would certainly fall into the ‘Trying to sell you something’ bucket, Eh?
You think? :) That is what OP asked for (how come people are not marketing jitter for cables).

Besides, you note that jitter-free doesn't exist. Yet there are all the claims of jitter-free transmission.

Dave
Yup. And those claims are non-sense.

faberryman

03-08-09, 03:36 PM

http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10236&cs_id=1023601&p_id=2743&seq=1&format=2

"This cable allows jitter-free transfer of digital audio signals."

http://www.providencecable.com/products.asp?cid=5786969
"Digital S/PDIF Cable for Maximum Sound with Minimal Noise. The digital data may be a precise set of zeroes and ones, but it takes a high-quality digital coax cable to reduce jitter, maximize data transfer and reject noise from outboard DACs, DAT machines or monitors. "

http://www.monstercable.com/productdisplay.asp?pin=3864
"Enhanced Jitter Reduction for Smoother, Natural Digital Audio
For truly dramatic home theater, digital audio is just as important as digital video. Unfortunately, jitter can be a serious problem in digital audio cables. This clock-signal error causes digital bits to be converted into analog waveforms with inaccurate phasing. This can distort the sound of your favorite movies and music. Ordinary coaxial audio cables with inferior construction can actually increase clock jitter. For the most accurate transmission of the digital bitstream and total enjoyment of your movies and music, choose the cable audiophiles trust: M1000DCX Digital Coaxial."

http://www.abccables.com/90-2681.html
"This cable connect dvd players to audio receivers, Sattelite boxes and cable boxes to audio receivers, computer audio equipment, and any other equipment that supports Coax(S/Pdif) interface interconnect. This cable allows jitter-free transfer of digital audio signals. "

http://www.purenote.com/alluvion_rca_digital_cable.htm
"Sonic Impression: Our Alluvion RCA digital cable is impedance matched to all 75 Ohm digital interfaces for jitter-free signal transmission. This renders a noiseless, black background and a precisely focused soundstage with lifelike musical clarity."

This was all from the first search page :).
There is no such thing as a jitter-free cable. There will always be digital interface jitter and cable-induced, pattern-dependent jitter. The only question is how much and how well it is controlled.

amirm

03-08-09, 03:38 PM

Actually, I think a lot of audio equipment is better than human hearing. I for one know that my hearing is flat from 20Hz to 20KHz.
On bandwidth, yes, they can exceed your ear. But in other respect, not yet.

Just look at the specs for any DAC. Here is a random one from TI: http://focus.ti.com/docs/prod/folders/print/pcm1753.html

"THD+N: 0.002%, Typical"

So the device is adding at least that much distortion to the audio as it is converting to analog. Look up the specs for A/D and you see yet another number for that. So with nothing else, you have sum of those for audio distortion. That distortion creates harmonic components not in the original signal. There is no data that says such distortion is not audible. And waveforms prove the input is not the same as the output.

faberryman

03-08-09, 03:42 PM

So the device is adding at least that much distortion to the audio as it is converting to analog. Look up the specs for A/D and you see yet another number for that. So with nothing else, you have sum of those for audio distortion. That distortion creates harmonic components not in the original signal. There is no data that says such distortion is not audible. And waveforms prove the input is not the same as the output.
Who knows how much distortion my ears, auditory canal, etc. is adding to the original sound.

thebland

03-08-09, 03:47 PM

Who knows how much distortion my ears, auditory canal, etc. is adding to the original sound.

Yes... exactly. Sometimes I wonder the need to mire one's self in the minutia of 'better sound'.. At a certain threshold, the digital stuff is likely all the same..

goneten

03-08-09, 03:49 PM

I paid over a hundred dollars just a week ago.

What a rip off !

Regards,

amirm

03-08-09, 03:53 PM

Who knows how much distortion my ears, auditory canal, etc. is adding to the original sound.
Yup. Until we understand how the ear works, we are shooting in the dark. We finally arrive at a key point. The ear is a super complex instrument. Yet, most of the research we have to design things for it date back many decades! Look at the hearing threshold curves from Fletcher and Munson. These go back to 1933! http://en.wikipedia.org/wiki/Fletcher-Munson_curves

Yet we sue those curves in everything from desiging compression algorithms to DAC filtering and design (noise shaping). Surely we could use more current research for the sake of audio fidelity, than to cure disease.

goneten

03-08-09, 03:54 PM

I've been involved in too many of these debates but I'll just say one thing : there is a difference between measurable phenomena and perceivable phenomena. ;)

Carry on. .

Regards,

dlarsen

03-08-09, 04:17 PM

There will always be digital interface jitter and cable-induced, pattern-dependent jitter. The only question is how much and how well it is controlled.

Indeed, we flat-earthers engineers with our small, limited closed minds use eye-patterns to define and measure the control limits. All of our high-speed differential interfaces (HDMI, DVI, USB, 1394, etc) are designed, built and tested to it. We know that if the setup, hold times, and noise margins are met, then we have reliable and repeatable data transmission and there isn't much room for the audible delta claims that Amir makes here.

Dave

Art Sonneborn

03-08-09, 04:44 PM

Who knows how much distortion my ears, auditory canal, etc. is adding to the original sound.

Or the resonance frequency of my burgeoning spare tire.

Art

faberryman

03-08-09, 04:49 PM

Indeed, we flat-earthers engineers with our small, limited closed minds use eye-patterns to define and measure the control limits. All of our high-speed differential interfaces (HDMI, DVI, USB, 1394, etc) are designed, built and tested to it. We know that if the setup, hold times, and noise margins are met, then we have reliable and repeatable data transmission and there isn't much room for the audible delta claims that Amir makes here.
I don't believe I ever made any claims about the audibility of digital interface jitter and cable-induced, pattern-dependent jitter, so I would appreciate your not inferring that I did. I merely said there is no such thing as a jitter free cable.

FrantzM

03-08-09, 04:58 PM

Hi

While it makes for a good looking argument.. The distortion added by the ear canals etc, are not relevant to the discussion.. The ears react the same way to the same stimuli...
We on this forum DO care about minute differences.. We can try to convince ourselves of the contrary but the results are there.. Who else but this really microscopic portion of the population would care about the differences between 3-chip and 1-chip or notice that the higher ANSI CR does "impart a new dimension" to the picture?? We DO! if there is a piece of gear that provide better performance or if there is a potential for such , we need to research it.... We have not hit the ceiling of performance be it digital or analog, we are very far from it... both in PQ and in AQ...

Glimmie

03-08-09, 05:36 PM

mmiles

03-09-09, 10:55 PM

All I can say is that Glimmie and Amirm are purdee smart fellars...

Welcome back Mark H (my fellow Maryland home boy)!

mark haflich

03-10-09, 12:08 AM

Thanks mmiles and cineramax and the good doctors.

khellandros66

03-10-09, 02:27 PM

Alimentall

03-10-09, 03:21 PM

So tell me how come packet loss does not occur over DSL lines when the wind is blowing or dampened in the rain??

Because they're on cable elevators ;)

amirm

03-10-09, 05:48 PM

So tell me how come packet loss does not occur over DSL lines when the wind is blowing or dampened in the rain??

0's and 1's will always be there. Now since HDMI doesnt use a "secured" connector I can see a loss of info under vibration. But as with all digital its either there or its not. There is no form of grey goo in the middle.
I thought we explained all of this. But here is a quick summary again.

The 1s and 0s are recoverd correctly as you state. No one is debating that one way or the other.

Sometime later, for audio, those samples need to become analog signals. The DAC needs three things to do that:

1. The sampe value. This is 100% there per above.

2. A reference voltage. This voltage is divided by the value told to output (more or less). This is an analog value. If this value is wrong, your output is wrong. If the value gets modulated (modifed) by something, then your output gets distorted.

3. A master clock. This tells the DAC when to output the samples. This clock must have accuracy down to trillionth of a second (based on math) for the last bit of a 16-bit value to be accurate.

High-speed activity on power supply lines and RF leakage/cross-talk cause #2 or #3 to ever so slightly change. When they do, you no longer have the same output. The characteristics of the cable (and noise induced on it) impacts the circuits at both end and that impact in return can modulate #2 or #3.

I hope everyone is in sync with above. I post papers outlining them.

What the disagreement is whether that impact is of any audible significance. The effect though on #2 and #3 can be measured and shown with instruments.

Net, net, we have an analog process when it comes to timing and clock for audio. The system is not all digital. It never has been despite misconceptions to the contrary.

Taking that info and passing over a $3.50 monoprice cable, vs a $800 snake oil brand, you aren't gonna see a difference, there is no interference... its either gonna show up, or its not.
I buy monoprice cables also. So that is neither here nor there. And for video, there is no issue because the final output is more or less digital (a pixel). So nothing "shows" up anywhere if you change HDMI cables.
Take what ya read about the intergrity of digital, especially when it comes to outside interference, with a grain of salt...

BTW I have years of experience in the IT field working with DSL, T1, OC3, Fiber, Copper, WAP, Wifi, etc...
None of which helps you here because the final output of all of those systems is digital. Not analog. Problem only comes up if you attempt to convert those digital samples to analog which we don't do in communication (sans dial-up and stuff like that). And try to listen to them.

John Kotches

03-11-09, 09:33 PM

So tell me how come packet loss does not occur over DSL lines when the wind is blowing or dampened in the rain??

0's and 1's will always be there.

This would seem to demonstrate a lack of understanding of the difference between protocols.

TCP/IP has acknowledgment packets (ACK) which return to the server side to indicate receipt. If an acknowledgment packet is not received for a series of packets they are retransmitted. The protocol also allows for out of order packet reassembly at the receiving end to account for the retransmitted packets.

By contrast HDMI is a real time operation with no retransmit capability. In this respect it's not dissimilar to media streaming across a network. Data can (and does) get lost.

Now since HDMI doesnt use a "secured" connector I can see a loss of info under vibration. But as with all digital its either there or its not. There is no form of grey goo in the middle.

So there's no such thing as data loss or corruption? Sorry, that's not valid. It has nothing to do with the connector in most cases either.

Taking that info and passing over a $3.50 monoprice cable, vs a $800 snake oil brand, you aren't gonna see a difference, there is no interference... its either gonna show up, or its not.

Construction, not price is the issue. Over longer lengths you need higher gauge, which does translate to a higher cost to prevent dropping your signal levels outside of spec.

Take what ya read about the intergrity of digital, especially when it comes to outside interference, with a grain of salt...

Right now, I think everyone should be taking your post with a grain of salt -- you haven't demonstrated an understanding in the differences between a data network and HDMI's topology.

BTW I have years of experience in the IT field working with DSL, T1, OC3, Fiber, Copper, WAP, Wifi, etc...

You are guilty of assigning properties of one "network" topology with another. My use of "network" is a rather loose usage as HDMI isn't really a network in the traditional sense.

I have years of experience in the IT field as well. It's not the same animal real time vs. non real time. See my previous about streaming media.