Any sound degradation from using a 3.5mm to dual RCA cable? - Page 2 - AVS Forum
Forum Jump: 
Reply
 
Thread Tools
post #31 of 119 Old 04-25-2014, 05:48 PM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,078
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 750 Post(s)
Liked: 434
Quote:
Originally Posted by arnyk View Post

OTOH there's a good chance that you've never ever heard audio without jitter from an analog source, as audible jitter is pretty common in even the best analog playback digital systems.
Interesting.
There is no chance of that Arny because there is no definition for "analog jitter." I can make up a name of a disease and say there is a good chance you have never contracted it. What's the value in that???

I put the term "analog jitter" in Wiki and it says this:

The page "Analog jitter" does not exist. You can ask for it to be created, but consider checking the search results below to see whether the topic is already covered."

I then searched for the same term in Audio Engineering Society site and I get this:

No results found for "analog jitter" site:aes.org.

So clearly this is a made up term and problem in analog systems.
Quote:
I will repeat a pretty good formal definition of jitter from http://en.wikipedia.org/wiki/Jitter

"Jitter is the undesired deviation from true periodicity of an assumed periodic signal in electronics and telecommunications, often in relation to a reference clock source. Jitter may be observed in characteristics such as the frequency of successive pulses, the signal amplitude, or phase of periodic signals."

Notice that it says "often in relation to a reference clock source" but not "always in relation to a reference clock source".
You are skipping the first part where it is says deviation from true periodicity of an assumed periodic signal." There is nothing periodic about analog signal which can be any and all things it wants, whether it repeats or not. It is a clock signal that repeats with periodicity and hence we can talk about its jitter. You can't buy into half the definition and not the other half Arny.

Quote:
Analog playback has a presumed time base just as surely as digital playback. In analog the presumed time base is related to the motion of the media that has the sound engraved on it (Vinyl) or embedded in it as magnetic variations (magnetic tape). Since the velocity of these media with respect to the stylus or playback head is prone to small variations, there is an variation in the time base of the signal just as surely as if it were sampled.

In reality all of these things are FM distortion.
Except that jitter in digital audio gets reduced to AM modulation as none of the other sidebands are significant. In sharp contrast, the speed variations in analog systems are so large that you have true FM modulation with many sidebands. The large variation in analog systems however does not have the same audible effect in digital systems since in the latter, the frequency of jitter can be quite high, forcing the distortions to show up in unmasked areas of the hearing system. This is the point I made in the other long thread.
Quote:
I can intentionally create digital jitter, analog flutter or FM distortion with the same modulating frequency and modulation index or degree of modulation and it will all sound pretty much the same.
This is a chisel:

Narex-Firmer-Chisel-811520-e1348262184535.jpg

This is a screwdriver:

screwdriver-1.jpg

Fact that they both have a non-metallic handle, a metal shaft and flat heads does not make them the same. Refer to the Chisel as a screwdriver in front of a woodworker and they wouldn't know what you are saying. So just because things are "pretty much the same" doesn't make them the same. It might to a layman not schooled in the engineering but not in a technical discussion here.
Quote:
There is even audio editing software that was originally designed for doing things like pitch correction that was found to be capable of identifying and correcting jitter in analog recordings:

http://www.celemony.com/en/start
I did a site search on that and could not find any reference to jitter. If that is back up to your argument to use the term jitter in analog systems, why don't they use it Arny?

Engineering is all about precision. We don't mix a surface mount capacitor with a resistor even though they may look identical. The moment you deviate from this attention to detail, then you are not in the domain of engineering. I am pretty sure we don't want to go there any more than we have already.
David Susilo likes this.

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
Sponsored Links
Advertisement
 
post #32 of 119 Old 04-25-2014, 06:17 PM
AVS Special Member
 
David Susilo's Avatar
 
Join Date: Aug 2002
Location: Markham, Canada
Posts: 9,599
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 289 Post(s)
Liked: 410
Arny, vibrato is something that needs to be learned, honed, and developed by any true vocalist. It is done deliberately and not the result of "timing error". I used to be a vocal coach for more than a decade for Royal Conservatory of Music in Canada and for Yamaha Music School in Australia and i have worked with many vocalists at Roy Thompson Hall and The Hummingbird Centre in Canada...please do not insult us with your "vocal vibrato is a jitter" argument. It is false, any musicologists and vocalists will disagree with you. Or tens of thousands of them are wrong and you are the only one who is right? Sigh...

follow my A/V tweets @davidsusilo

ISF, THX, CEDIA, Control4 & HAA certified
Reviewer for TED, QAV, AUVI & DownUnder Audio Magazine


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

David Susilo is offline  
post #33 of 119 Old 04-26-2014, 06:21 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,381
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 747 Post(s)
Liked: 1161
Quote:
Originally Posted by David Susilo View Post

Arny, vibrato is something that needs to be learned, honed, and developed by any true vocalist. It is done deliberately and not the result of "timing error". I used to be a vocal coach for more than a decade for Royal Conservatory of Music in Canada and for Yamaha Music School in Australia and i have worked with many vocalists at Roy Thompson Hall and The Hummingbird Centre in Canada...please do not insult us with your "vocal vibrato is a jitter" argument. It is false, any musicologists and vocalists will disagree with you. Or tens of thousands of them are wrong and you are the only one who is right? Sigh.

The above completely misses the point.

In fact it is highly likely that a person hearing a vocal track with a lot of jitter applied will remark on how much it makes the vocalist sound like he has vibrato even if he is not singing that way.

The above comment also obfuscates the fact that vibrato in music is not just a vocal affect but one that is applied to the playing of many instruments, perhaps string instruments being the most common and obviously applied.

For example here's a well-illustrated lesson on playing a violin with vibrato: http://www.wikihow.com/Do-Vibrato-on-a-Violin

And also for the guitar: http://en.wikibooks.org/wiki/Guitar/Bending_and_Vibrato

"Bending and vibrato are two related effects which help give extra "life" to notes, especially sustained notes, by changing their pitch."

FM distortion in audio reproduction whether digital, analog, or loudspeakers accomplishes the same outcome - it applies a periodic change to the pitch of the recording.

What I take away from the above post is that I'm dealing with people who have never heard a digital system with enough jitter so that they would naturally perceive how it can sound the same as the Jitter or FM distoriton or Flutter or Wow that is common in analog recording.

BTW if one measures any of these effects (which I have) the same sideband structure can be seen in the spectral analysis. IOW the sideband structure we see arising from digital jitter are also present in recordings that are contaminated by flutter and wow from analog recordings, FM distortion from loudpseakers, and even vibrato in notes played on certain musical instruments.

Case in point:

LP playback on a Linn TT:

http://www.stereophile.com/content/linn-lp-playing-system-measurements




Another example of jitter in the playback of analog tape:

http://www.tapeheads.net/showpost.php?s=678b29be20bfc422833ce98925f880bd&p=227183&postcount=10

"The pictures below show the FFT spectrum of 3150 Hz tone recorded and replayed on Sony K808ES deck (upper panel) and replayed on Aiwa deck (lower panel)."




This paper specifically analyzes vibrato in music and characterizes it as FM modulation:

http://www.researchgate.net/publication/228556411_Perceptual_Evaluation_of_Vibrato_Models/file/3deec52612a83c8b3d.pdf

BY the musical term vibrato usually relates to FM modulation while tremolo usually relates to AM modulation. Sometimes they are conflated but that is arguably a mistake (not an uncommon one).

In short, the duck argument seems to apply. Flutter and wow and vibrato and FM distortion in speakers looks like jitter on a FFT, sounds like jitter if you hear it... ;-)


I don't know how clearer this can be made, given the level of expertise in audio that seems to be limiting the comprehension of the relevant points in this discussion.
CruelInventions likes this.
arnyk is offline  
post #34 of 119 Old 04-26-2014, 06:36 AM
Super Moderator
 
DrDon's Avatar
 
Join Date: Mar 2002
Location: Metro Detroit
Posts: 12,657
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 70 Post(s)
Liked: 264
Uhm.... topic? Yeah, let's stay on that.

Walking the fine line between jaw-dropping and a plain ol' yawn.
DrDon is offline  
post #35 of 119 Old 04-26-2014, 08:44 AM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,078
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 750 Post(s)
Liked: 434
Quote:
Originally Posted by arnyk View Post

BTW if one measures any of these effects (which I have) the same sideband structure can be seen in the spectral analysis. IOW the sideband structure we see arising from digital jitter are also present in recordings that are contaminated by flutter and wow from analog recordings, FM distortion from loudpseakers, and even vibrato in notes played on certain musical instruments. Case in point: LP playback on a Linn TT: http://www.stereophile.com/content/linn-lp-playing-system-measurements

Thank you as always for your detailed responses Arny. They help advance the discussion.

I hope you don't mind but I took the liberty of superimposing the jitter in AVRs that I tested last year over that measurement of Linn Turntable. This is what that looks like:

i-gCxqtqc-XL.png

As you see I matched the span to be +- 200 Hz as the turntable measurements were. I also pulled up the turntable a bit since it was not using 0 dbFS and my measurements were.

We see the situation that I have been lamenting for a while. That our digital systems decades later often sink down to analog performance instead of what they are capable of producing. Here we see that our two AVRs actually have more low frequency jitter than that the turntable since the tone has been widened (ideal system would have a single spike which is our original test tone and nothing else). You can easily see how the blue curve is wider than the gray from Linn turntable.

Even going past that area the performance of the digital system is not that much better than this turntable. The blue line for example touches the gray in a couple of places.

That Linn review was done in 2003. My measurements were in 2013 or a decade later. Yet when we focus on low-frequency "jitter" we are hardly better than that ancient standard.

Thankfully the above analysis is for nothing. Low frequency modulation sidebands are nearly always masked. This is why no one listening to that Linn turntable would complain about speed variations. Here is a nice paragraph from Dr. Toole's Book:

"Auditory masking is a natural perceptual phenomenon, operating in live concert situations just as it does in sound reproduction. It has assisted our musical enjoyment by suppressing audience noises during live performances and, over several decades, by rendering LPs more pleasurable. If we talk here about compressing data, it would be fair to say that LPs perform “data expansion,” adding unmusical information in the form of crosstalk, noise, and distortions of many kinds. More comes off of the LP than was in the original master tape. However, because of those very same masking phenomena that allow perceptual data reduction systems to work, the noises and distortions are perceptually attenuated. So successful is this perceptual noise and distortion reduction, that good LPs played on good systems can still sound impressive."

And here is our dichotomy. Analog systems have modulated distortions at very low frequencies where the power of masking is the highest. It is the nature of their system to not want to vary at high frequencies because the mass of the platter doesn't allow it. That mass acts like an excellent low-pass filter allowing only slow speed changes to get into the system. That then translates into masking effect being very strong here.

In digital systems, we also have a low-pass filter (in the phase locked loop). But what is "low" there is many thousands of hertz as compared to tens of hertz in analog domain. As a result we can't rely on masking as much as analog does. Of course there are excellent digital systems that keep the distortions very low but such is not the case with mass market products over HDMI as I have shown.

Net, net, this argument backfires on us when we actually apply psychoacoustics to it. Without that, sure, it looks like we had tons of distortion in analog yet there are plenty of people who like it even more than digital. But with the science of how we hear applied to it, the tables turn, pun intended biggrin.gif, and bring out the reason why analog users are "lucky" with respect to such speed modulations. They have a lot more distortion but their distortion is a lot less audible. Digital systems have a lot less distortion but the type they have can be a lot more audible.

The only way to fix this situation is to have high-performance implementations which unfortunately are not the domain of dollar store audio products. Taking us back to Arny's first post in this thread, digital systems are inherently hard to get right and this comparison shows that. They draw from expertise of two domains of electronics, analog and digital, which usually do not mix and are often segregated. The person designing pure analog systems doesn’t have this problem as he is focused in one domain only. So his job in some sense is much easier.

My recommendation is that we don't try to equate speed variations in analog to jitter in digital. Nothing good comes out of it for our cause. smile.gif

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #36 of 119 Old 04-26-2014, 09:56 AM
AVS Special Member
 
Frank Derks's Avatar
 
Join Date: Jul 2002
Location: Region A,B,C
Posts: 1,891
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 98 Post(s)
Liked: 89
Amir, you can't overlay like this and make a comparison. The conclusion will be wrong. "Yet when we focus on low-frequency "jitter" we are hardly better than that ancient standard"

The linn shows a 100Hz modulation by flutter with a 1kHz test tone 1:10 (There us also a spike at about 990Hz at -46dB. my guess it's the wow)

The pioneer avr shows the highest spike at 11974 with a 12kHz testtone. 1:480

The linn with a test tone at 12kHz with the 100Hz modulation will have a spike at 11.9kHz. This is a wider jitter spectrum than that of the pioneer.
The reverse will happen if the 12kHz test tone is scaled back to 1Khz. The jitter spectrum will scale down to.

The significance of the audible difference of flutter of a 1kHz versus a 12kHz test tone is why usually a logarithmic x axis scale is used.
Frank Derks is online now  
post #37 of 119 Old 04-26-2014, 12:25 PM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,078
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 750 Post(s)
Liked: 434
Quote:
Originally Posted by Frank Derks View Post

The significance of the audible difference of flutter of a 1kHz versus a 12kHz test tone is why usually a logarithmic x axis scale is used.
There is no 1Khz distortion in either the stereophile graph or what I post. Both scales are matched in both amplitude and *span* of frequencies. Both have 200 Hz to the left and right of the main tone. As such, neither extends to 1000 Hz as you say. And I don't know how you determined the Linn measurements are in log scale:



The ticks are all equally distanced which means it is a linear graph as is mine, not log.

The logic of the rest of your post escapes me so someone else who is able to follow it would need to explain.

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #38 of 119 Old 04-26-2014, 02:14 PM
AVS Special Member
 
Frank Derks's Avatar
 
Join Date: Jul 2002
Location: Region A,B,C
Posts: 1,891
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 98 Post(s)
Liked: 89
Quote:
Originally Posted by amirm View Post

There is no 1Khz distortion in either the stereophile graph or what I post. Both scales are matched in both amplitude and *span* of frequencies. Both have 200 Hz to the left and right of the main tone. As such, neither extends to 1000 Hz as you say. And I don't know how you determined the Linn measurements are in log scale:



The ticks are all equally distanced which means it is a linear graph as is mine, not log.

The logic of the rest of your post escapes me so someone else who is able to follow it would need to explain.

It's not 1kHz distortion it's the 1kHz test signal from a test record.
The linn graph shows peaks at 900, 950 and 1050 and 1050 (notice the 50Hz intervals). Another set of peaks at (approx.). 967, 978 ,989 and 1011, 1022 and 1033.

Your reasoning in your post was flawed.Overlaying a graph with a 1kHz TEST signal with one using a 12kHz test signal is apples to oranges.
You need to overlay test where both use the same test signal frequency. At 1kHz the jitter spectrum for the avr will be very different because more samples (48) are available as opposed to the 4 at 12kHz. This reduces the effect of the jitter at a 1kHz test signal for digital significantly..

A distortion component 100Hz under and above a 1Khz test signal isn't masked. a distortion component 25Hz under and above a 12kHz test signal will be masked.

It's the matter of audibility where a logarithmic scale for frequency range plot becomes more useful.
Frank Derks is online now  
post #39 of 119 Old 04-26-2014, 07:43 PM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,078
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 750 Post(s)
Liked: 434
Quote:
Originally Posted by Frank Derks View Post

A distortion component 100Hz under and above a 1Khz test signal isn't masked.
I think it will be a very useful exercise to see how you arrived at that conclusion. Would you please describe the CBR and ERB and delta F for 1Khz and how the -70 db tone falls in them? Saves me a bunch of work to do the same smile.gif. Please also include the references you are using for those thresholds.

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #40 of 119 Old 04-26-2014, 09:59 PM
 
gazoink's Avatar
 
Join Date: Apr 2014
Posts: 68
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
Quote:
Originally Posted by arnyk View Post


The above completely misses the point.

In fact it is highly likely that a person hearing a vocal track with a lot of jitter applied will remark on how much it makes the vocalist sound like he has vibrato even if he is not singing that way.

The above comment also obfuscates the fact that vibrato in music is not just a vocal affect but one that is applied to the playing of many instruments, perhaps string instruments being the most common and obviously applied.

For example here's a well-illustrated lesson on playing a violin with vibrato: http://www.wikihow.com/Do-Vibrato-on-a-Violin

And also for the guitar: http://en.wikibooks.org/wiki/Guitar/Bending_and_Vibrato

"Bending and vibrato are two related effects which help give extra "life" to notes, especially sustained notes, by changing their pitch."

FM distortion in audio reproduction whether digital, analog, or loudspeakers accomplishes the same outcome - it applies a periodic change to the pitch of the recording.

What I take away from the above post is that I'm dealing with people who have never heard a digital system with enough jitter so that they would naturally perceive how it can sound the same as the Jitter or FM distoriton or Flutter or Wow that is common in analog recording.

BTW if one measures any of these effects (which I have) the same sideband structure can be seen in the spectral analysis. IOW the sideband structure we see arising from digital jitter are also present in recordings that are contaminated by flutter and wow from analog recordings, FM distortion from loudpseakers, and even vibrato in notes played on certain musical instruments.

Case in point:

LP playback on a Linn TT:

http://www.stereophile.com/content/linn-lp-playing-system-measurements

<snip>
Another example of jitter in the playback of analog tape:

http://www.tapeheads.net/showpost.php?s=678b29be20bfc422833ce98925f880bd&p=227183&postcount=10

"The pictures below show the FFT spectrum of 3150 Hz tone recorded and replayed on Sony K808ES deck (upper panel) and replayed on Aiwa deck (lower panel)."

<snip>


This paper specifically analyzes vibrato in music and characterizes it as FM modulation:

http://www.researchgate.net/publication/228556411_Perceptual_Evaluation_of_Vibrato_Models/file/3deec52612a83c8b3d.pdf

BY the musical term vibrato usually relates to FM modulation while tremolo usually relates to AM modulation. Sometimes they are conflated but that is arguably a mistake (not an uncommon one).

In short, the duck argument seems to apply. Flutter and wow and vibrato and FM distortion in speakers looks like jitter on a FFT, sounds like jitter if you hear it... ;-)


I don't know how clearer this can be made, given the level of expertise in audio that seems to be limiting the comprehension of the relevant points in this discussion.

+1 Arnie.  Dead on.  Clearly these "experts" have never heard of "scape flutter", another analog manifestation of "jitter" (by any other name...).  Scape flutter in an analog tape recorder is a high frequency variation in longitudinal tape speed caused by tape passing over stationary items in the tape path, followed by unsupported spans.  The resulting high frequency FM causes a form of distortion that manifests itself as noise around otherwise pure tones, but only in the presence of a signal, and when taken to extreme lends a sort of grittyness. Sound familiar?  Like perhaps...um...digital jitter when taken to extreme??  The same thing exists to greater or lesser extents in all forms of analog recording and reproduction.   It's dealt with by avoiding stationary tape path components (making them rollers, for example) and keeping the tape supported as much as possible.  But it's never really gone, and is always far more audible than typical digital jitter. Just because we never called it "Jitter" doesn't mean the results aren't identical.  If it looks like a duck and sounds like a duck...

gazoink is offline  
post #41 of 119 Old 04-27-2014, 09:09 AM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,078
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 750 Post(s)
Liked: 434
Quote:
Originally Posted by gazoink View Post

+1 Arnie.  Dead on.  Clearly these "experts" have never heard of "scape flutter", another analog manifestation of "jitter" (by any other name...).  Scape flutter in an analog tape recorder is a high frequency variation in longitudinal tape speed caused by tape passing over stationary items in the tape path, followed by unsupported spans.  The resulting high frequency FM causes a form of distortion that manifests itself as noise around otherwise pure tones, but only in the presence of a signal, and when taken to extreme lends a sort of grittyness. Sound familiar?  Like perhaps...um...digital jitter when taken to extreme??  The same thing exists to greater or lesser extents in all forms of analog recording and reproduction.   It's dealt with by avoiding stationary tape path components (making them rollers, for example) and keeping the tape supported as much as possible.  But it's never really gone, and is always far more audible than typical digital jitter. Just because we never called it "Jitter" doesn't mean the results aren't identical.  If it looks like a duck and sounds like a duck...
Before I respond, I see that you just registered. Let me extend a warm welcome to you. We have driven all the "analog heads" out of here so it is nice to see someone join that still speaks the language smile.gif.

As to your post, I think we are talking past each other. No one here says tape decks and turntables have no speed variations. Of course they do. We are objecting to use of the term "jitter" in that context where no paper or reference ever does that. It might be useful to step back and see where the term jitter came from in the context of digital audio.

Jitter in digital systems had existed long before it was applied to digital audio. It described variations, usually in the clock signal in synchronous systems which can cause the behavior of the system to change unexpectedly. Here is a simple animation of that which I have put together:

i-SZ27qj9-XL.gif

Every DAC has a clock signal just like the above waveform. Its variations then naturally was called jitter.

Analog systems have no clock. There is no "tick" that tells them to do something and then wait for the next tick. There are no discrete steps. If there is speed variation, it travels in a continuous rather than sampled manner. Because of these factors, it made no sense to call the clock variations "flutter" as that term was used in analog systems. The better and correct term was jitter as the effect was just like other digital systems.

As I noted to Arny, there is no paper, dictionary or reference of any sort that uses the term "jitter" to describe speed variations in analog systems. Its application then in that domain, is problematic. All the "experts" in the world can't be wrong in using flutter for analog systems, and jitter for digital.

Note that we can easily measure jitter in digital systems because we can create a very pure reference. This is not the case with analog systems. Since your recorder has speed variations that cannot be brought down anywhere close to what we can do in digital systems, what you measure at playback time, or hear, is combination of speed variations in the recording and playback systems. This is another reason why you don't want to use terms reserved for digital systems and apply them to analog.

As to knowing about scape flutter, I know what a scrape roller is. And yes, if you a worn out one it can create flutter just like any other mechanical thing causing the same in the tape path. I had not heard of the term "scape flutter" and I am sure no one else had heard of it here either. I googled the tapeproject web site and forum and there is no mention of that phrase or even scape roller for that matter. So the notion that we don't know what we are talking about because we haven't heard of a term no one else is using, is non sequitur. Not knowing a term that hardly anyone uses does not make us dummies smile.gif. All of this said, sure, you can call flutter created by scrape roller "scrape flutter" if you could isolate the effect to just that. I will note however that you did not call it "scape jitter!"

Bringing focus to the discussion, this thread is about a PC sound card. There is no analog tape involved in that reproduction system. So the whole notion of talking about analog speed variations -- whatever you may call it -- is an argument looking for a reason to exist. Arny usually brings this up to trivialize digital jitter as to say, "folks were too dumb to hear it in analogy, why are we worried about it in digital?" You saying that analog "jitter" is quite audible in the case of scape flutter, actually goes against what he wants to argue. So in that sense, you are not at all in agreement with his motivation to bring up the topic of analog flutter in the context of digital systems.

Anyway, thanks for the comments and the trip back to our old tape formats.
David Susilo likes this.

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #42 of 119 Old 04-27-2014, 11:28 AM
AVS Special Member
 
blazar's Avatar
 
Join Date: Oct 2004
Location: USA
Posts: 2,267
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 45 Post(s)
Liked: 243
Quote:
Originally Posted by arnyk View Post

Interesting that with all that alleged noise, there are sound cards that have noise as low as even some of the best audio gear.

Reality is that any piece of audio gear with digital circuits inside it has a built-in noise problem, and guess what - even stand alone DACs have digital circuits inside them.

Reality is that there is a area of equipment design called :Mixed signal circuits" that is all about mixing digital and audio circuits in the same box without problems.

Consider a DAC chip - one side of the chip is digital with all the noise that you fear, the other side is analog. They are tiny fractions of an inch apart. No magic, just the art of mixed signal design paying off.

Another example - AVRs. They are now chock full of digital circuits for both audio and video, and the ones with Class D power amps also have switchmode power supplies that would put all but the very largest PC power supplies to shame.

Here are the specs of the analog outputs of an audio interfact that I own:

http://www.lynxstudio.com/pop/product_file.asp?i=22

Frequency Response 20 - 20 kHz, ± 0.05 dB at 44.1 kHz sample rate

Dynamic Range 117 dB, A-wtd.

Signal-to-Noise 117 dB, A-wtd.
Channel Crosstalk <-120 dB,
1 kHz signal @ -1dBFS

THD+N -97 dB (0.0014%) @ -1 dBFS
-104 dB (0.0006%) @ -8 dBFS
1kHz signal, 22Hz - 22kHz BW

It's an ordinary PCI with no special shields, etc:



I've tested it - they tell no lies! ;-)

Look at trinnov's high end boxes... All basically PC based

Blazar!
blazar is offline  
post #43 of 119 Old 04-27-2014, 02:45 PM
Senior Member
 
hevi's Avatar
 
Join Date: Jan 2007
Posts: 365
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 33 Post(s)
Liked: 48
Quote:
Originally Posted by Frank Derks View Post

It's not 1kHz distortion it's the 1kHz test signal from a test record.
The linn graph shows peaks at 900, 950 and 1050 and 1050 (notice the 50Hz intervals). Another set of peaks at (approx.). 967, 978 ,989 and 1011, 1022 and 1033.

Your reasoning in your post was flawed.Overlaying a graph with a 1kHz TEST signal with one using a 12kHz test signal is apples to oranges.
You need to overlay test where both use the same test signal frequency. At 1kHz the jitter spectrum for the avr will be very different because more samples (48) are available as opposed to the 4 at 12kHz. This reduces the effect of the jitter at a 1kHz test signal for digital significantly..

A distortion component 100Hz under and above a 1Khz test signal isn't masked. a distortion component 25Hz under and above a 12kHz test signal will be masked.

It's the matter of audibility where a logarithmic scale for frequency range plot becomes more useful.

Modulation theory 101:
If say, you have a carrier frequency of 440Hz and *frequency modulate* that with say 7 Hz (that is, you cross the 440Hz boundary 7 times a second and have an ideal sinusodial frequency modulation) you'll get your main side bands at +-7Hz from the 440Hz carrier (at 433 and 447Hz).

Modulate the frequency (with 7Hz) between say 435Hz and 445Hz (10Hz span), your side bands will be located at 433 and 447Hz, but attenuated compared to the carrier with about 8-9dB.

Now, if you modulate the frequency (with 7Hz) between only 449,5 to 440,5Hz (1Hz span), your side bands will still be located at *drumroll* 433 and 447Hz, but attenuated to the carrier with about 28dB, which is significantly less than in the previous case.

hevi is offline  
post #44 of 119 Old 04-27-2014, 09:17 PM
 
gazoink's Avatar
 
Join Date: Apr 2014
Posts: 68
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
Quote:
Originally Posted by amirm View Post


Before I respond, I see that you just registered. Let me extend a warm welcome to you. We have driven all the "analog heads" out of here so it is nice to see someone join that still speaks the language smile.gif.
Thanks.  That's a significant improvement over the first response I got, which was apparently deleted here, though I have the email.  Wow.  Suffice it to say thanks to the first reply I now own a new orifice. 
Quote:
Originally Posted by amirm View Post


Before I respond, I see that you just registered. Let me extend a warm welcome to you. We have driven all the "analog heads" out of here so it is nice to see someone join that still speaks the language smile.gif.

As to your post, I think we are talking past each other. No one here says tape decks and turntables have no speed variations. Of course they do. We are objecting to use of the term "jitter" in that context where no paper or reference ever does that. It might be useful to step back and see where the term jitter came from in the context of digital audio.

Jitter in digital systems had existed long before it was applied to digital audio. It described variations, usually in the clock signal in synchronous systems which can cause the behavior of the system to change unexpectedly. Here is a simple animation of that which I have put together:

i-SZ27qj9-XL.gif

Every DAC has a clock signal just like the above waveform. Its variations then naturally was called jitter.

Analog systems have no clock. There is no "tick" that tells them to do something and then wait for the next tick. There are no discrete steps. If there is speed variation, it travels in a continuous rather than sampled manner. Because of these factors, it made no sense to call the clock variations "flutter" as that term was used in analog systems. The better and correct term was jitter as the effect was just like other digital systems.

As I noted to Arny, there is no paper, dictionary or reference of any sort that uses the term "jitter" to describe speed variations in analog systems. Its application then in that domain, is problematic. All the "experts" in the world can't be wrong in using flutter for analog systems, and jitter for digital.

Note that we can easily measure jitter in digital systems because we can create a very pure reference. This is not the case with analog systems. Since your recorder has speed variations that cannot be brought down anywhere close to what we can do in digital systems, what you measure at playback time, or hear, is combination of speed variations in the recording and playback systems. This is another reason why you don't want to use terms reserved for digital systems and apply them to analog.

As to knowing about scape flutter, I know what a scrape roller is. And yes, if you a worn out one it can create flutter just like any other mechanical thing causing the same in the tape path. I had not heard of the term "scape flutter" and I am sure no one else had heard of it here either. I googled the tapeproject web site and forum and there is no mention of that phrase or even scape roller for that matter. So the notion that we don't know what we are talking about because we haven't heard of a term no one else is using, is non sequitur. Not knowing a term that hardly anyone uses does not make us dummies smile.gif. All of this said, sure, you can call flutter created by scrape roller "scrape flutter" if you could isolate the effect to just that. I will note however that you did not call it "scape jitter!"

Bringing focus to the discussion, this thread is about a PC sound card. There is no analog tape involved in that reproduction system. So the whole notion of talking about analog speed variations -- whatever you may call it -- is an argument looking for a reason to exist. Arny usually brings this up to trivialize digital jitter as to say, "folks were too dumb to hear it in analogy, why are we worried about it in digital?" You saying that analog "jitter" is quite audible in the case of scape flutter, actually goes against what he wants to argue. So in that sense, you are not at all in agreement with his motivation to bring up the topic of analog flutter in the context of digital systems.

Anyway, thanks for the comments and the trip back to our old tape formats.

Very surprised to see that "scrape flutter", a rather common term in the analog tape world, is unknown to the experts here.  Dale Manquen has written extensively about it, though for some reason the links to his papers on his site are broken.  His Altair T2DS (Tape Transport Diagnostic Syste), of which I've own two, is the only commercial unit produced to properly quantify high frequency flutter components, and his papers surrounding the development of that unit tell the whole story.  Again, sorry, the links are broken.  I have them on paper, not at arms reach.  But, try http://en.wikipedia.org/wiki/Wow_and_flutter_measurement#Scrape_flutter  That should help you understand what it is, and that it is in fact a well established term.

 

The results of jitter is a frequency modulation component of all related audio.  The result of scrape flutter is a frequency modulation component of all audio.  Yes, the mechanisms are different, the result is different in degree, modulation index, and the resulting spectra, but both jitter and scrape flutter...really all flutter...apply FM to the related audio.  I've never applied the term "Jitter" to tape specifically or any analog system, nor have I applied "scrape flutter" to a digital system, other than to highlight a valid comparison of the two.  However, FM is FM, regardless if caused by digital jitter or analog speed variation, or a varactor diode in a modulated oscillator.  And the result of FM is always new frequency products surrounding the carrier (audio in this case), regardless of the frequency of modulation, or the modulating wave form.  I'm sorry if you can't see the similarity

 

Thanks for the detailed explanation about jitter.  I'll take no offense since you don't know me or my background.  

 

And now back to our regularly scheduled topic:

I haven't had a problem with the reliability a 1/8" mini plug or jack that I can recall, though I've often had wires break where then enter the connector, strain relief or not.  I wouldn't worry about that connector adversely impacting audio from a sound card, though if it's a psychological problem for anyone, there are plenty of external sound cards that use other connectors from RCA to XLR to TRS.  There should be something in there that gives nearly everyone a warm/fuzzy.

gazoink is offline  
post #45 of 119 Old 04-28-2014, 05:01 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,381
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 747 Post(s)
Liked: 1161
Quote:
Originally Posted by blazar View Post

Quote:
Originally Posted by arnyk View Post

Interesting that with all that alleged noise, there are sound cards that have noise as low as even some of the best audio gear.

Reality is that any piece of audio gear with digital circuits inside it has a built-in noise problem, and guess what - even stand alone DACs have digital circuits inside them.

Reality is that there is a area of equipment design called :Mixed signal circuits" that is all about mixing digital and audio circuits in the same box without problems.

Consider a DAC chip - one side of the chip is digital with all the noise that you fear, the other side is analog. They are tiny fractions of an inch apart. No magic, just the art of mixed signal design paying off.

Another example - AVRs. They are now chock full of digital circuits for both audio and video, and the ones with Class D power amps also have switchmode power supplies that would put all but the very largest PC power supplies to shame.

Here are the specs of the analog outputs of an audio interfact that I own:

http://www.lynxstudio.com/pop/product_file.asp?i=22

Frequency Response 20 - 20 kHz, ± 0.05 dB at 44.1 kHz sample rate

Dynamic Range 117 dB, A-wtd.

Signal-to-Noise 117 dB, A-wtd.
Channel Crosstalk <-120 dB,
1 kHz signal @ -1dBFS

THD+N -97 dB (0.0014%) @ -1 dBFS
-104 dB (0.0006%) @ -8 dBFS
1kHz signal, 22Hz - 22kHz BW

It's an ordinary PCI with no special shields, etc:



I've tested it - they tell no lies! ;-)

Look at trinnov's high end boxes... All basically PC based

Seems completely credible. The world is full of gear that has an embedded PC. In the old days people even used PC chassis as a framework for audio gear. These days a fairly powerful full-function PC including mass storarge fits on a small circuit board so the embedded PC can be almost totally invisible. Due to the costs associated with licensing Windows royalty-fee versions of Linux have largely filled the same function. The processing power provided by ARM CPUs has increased to the point where they can perform many functions that used to be reserved for PCs.
arnyk is offline  
post #46 of 119 Old 04-28-2014, 05:34 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,381
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 747 Post(s)
Liked: 1161
Quote:
Originally Posted by hevi View Post

Quote:
Originally Posted by Frank Derks View Post

It's not 1kHz distortion it's the 1kHz test signal from a test record.
The linn graph shows peaks at 900, 950 and 1050 and 1050 (notice the 50Hz intervals). Another set of peaks at (approx.). 967, 978 ,989 and 1011, 1022 and 1033.

Your reasoning in your post was flawed.Overlaying a graph with a 1kHz TEST signal with one using a 12kHz test signal is apples to oranges.
You need to overlay test where both use the same test signal frequency. At 1kHz the jitter spectrum for the avr will be very different because more samples (48) are available as opposed to the 4 at 12kHz. This reduces the effect of the jitter at a 1kHz test signal for digital significantly..

A distortion component 100Hz under and above a 1Khz test signal isn't masked. a distortion component 25Hz under and above a 12kHz test signal will be masked.

It's the matter of audibility where a logarithmic scale for frequency range plot becomes more useful.

Modulation theory 101:
If say, you have a carrier frequency of 440Hz and *frequency modulate* that with say 7 Hz (that is, you cross the 440Hz boundary 7 times a second and have an ideal sinusodial frequency modulation) you'll get your main side bands at +-7Hz from the 440Hz carrier (at 433 and 447Hz).

Modulate the frequency (with 7Hz) between say 435Hz and 445Hz (10Hz span), your side bands will be located at 433 and 447Hz, but attenuated compared to the carrier with about 8-9dB.

Now, if you modulate the frequency (with 7Hz) between only 449,5 to 440,5Hz (1Hz span), your side bands will still be located at *drumroll* 433 and 447Hz, but attenuated to the carrier with about 28dB, which is significantly less than in the previous case.

To continue, in FM/PM modulation the amplitude of the sidebands will vary with the frequency being modulated. So using a test tone of 1 Khz and 10 KHz will produce sidebands with different amplitudes. It will also possibly produce different (more sidebands).

Here's an example:

This is the spectrum of a 1 KHz pure tone modulated 0.1 pct with 60 Hz:



This is the spectrum of a 10 KHz pure tone modulated 0.1 pct with 60 Hz:



In both case we see similar sideband but not identical and not perfectly scalable sideband structures. The primary sidebands in both cases are 60 Hz (the modulating frequency) from the carrier. While the amplitude of the primary sidebands @ 1kHz are about -43 dB down, amplitude of the primary sidebands @ 10 KHz carrier frequency are about -23 dB down. This maps well into the difference in carrier frequencies (10x = 20 dB) , per theory. BTW the sideband structures are dependent on the Modulation Index which is more complex number based on a number of things, and can be estimated using Bessel Functions.

The general rule is that running a jitter/FM/wow & flutter test with a higher frequency test signal increases the size of the primary artifact(s) roughly proportionately to the increase in the test signal frequency. Using a Modulation index that increases the number of sidebands takes energy away from the primary sidebands, usually just a little.

IOW, I can make jitter look as bad as I want for naive readers by jacking up the test frequency.

Jitter tests from the days of analog media were run using signals in the 3- 4 KHz range partially because using higher frequency signals did not give really reliable results since the basic media was so inherently limited. In contrast with digital we can run the test frequency and amplitude as high as we need to in-band in order to get the artifacts visible on a FFT.

If I correct Amir's erroneous plot (my work is hasty and therefore crude- IMO its up to him to do it right! ) I come up with this:



I will comment on the audibility issues separately.
Frank Derks likes this.
arnyk is offline  
post #47 of 119 Old 04-28-2014, 05:58 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,381
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 747 Post(s)
Liked: 1161
Quote:
Originally Posted by David Susilo View Post

Arny, no musicologist will define "vibrato" as "jitter".

So what? Terms of art naturally vary with the art, no?

http://legal-dictionary.thefreedictionary.com/Term+of+Art

"A word or phrase that has special meaning in a particular context.

A term of art is a word or phrase that has a particular meaning. Terms of art abound in the law. For example, the phrase double jeopardy can be used in common parlance to describe any situation that poses two risks. In the law, Double Jeopardy refers specifically to an impermissible second trial of a defendant for the same offense that gave rise to the first trial."

I'm also sure that if I searched enough I could probably find a musicologist who was also technologically savvy enough to realize the connection. ;-)
arnyk is offline  
post #48 of 119 Old 04-28-2014, 07:39 AM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,078
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 750 Post(s)
Liked: 434
Quote:
Originally Posted by arnyk View Post

If I correct Amir's erroneous plot (my work is hasty and therefore crude- IMO its up to him to do it right! ) I come up with this:

Good morning Arny. Good to see you posting here again.

I would be happy to find any mistakes in my graph but I am puzzled as to what you are doing above. Looks like you pulled down the AVR measurements to -110 db which is not correct. The bottom for that was -100 and the bottom for Linn at -90. The tops were essentially the same and both have the same size grid. As such, the Linn measurements need to stop at half grid mark from the bottom as I showed. In yours, the Linn bottom line is at -105 which does not match the stereophile measurements. Here are the two graphs side-by-side with the same scale that I used:

i-tPkk5LJ-X3.png
As a quick check, the Pioneer AVR has sideband peaks that reach almost to -70 dB. If you draw the same line for the Linn, you have no choice but to see them touch and they do in mine but not in yours.

Distortion at -70 db is "analog like" as I mentioned and this demonstrates that point nicely.

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #49 of 119 Old 04-28-2014, 07:57 AM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,078
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 750 Post(s)
Liked: 434
Quote:
Originally Posted by blazar View Post

Look at trinnov's high end boxes... All basically PC based
The Trinnov is high-end with respect to its acoustic processing. They use Pro multi-channel sound cards that cost more than a couple of PCs each! That is why it is so expensive. The machine is not your typical "high-end" audio equipment.

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #50 of 119 Old 04-28-2014, 08:13 AM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,078
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 750 Post(s)
Liked: 434
Quote:
Originally Posted by gazoink View Post

Very surprised to see that "scrape flutter", a rather common term in the analog tape world, is unknown to the experts here.
What is unknown to us and everybody else is what you originally said: "scape flutter." Note lack of "r" in there. Sounds like you meant scrape flutter in which case I mentioned we know what that is. Please read my response to you carefully and note my use of the term "scrape" vs your "scape."
Quote:
The results of jitter is a frequency modulation component of all related audio.... I'm sorry if you can't see the similarity
We not only see the similarity, but we already said the same! See this post that I linked to just a few posts above yours: http://www.avsforum.com/t/1340051/seeking-education-about-those-ultra-expensive-interconnects/1830#post_20710842. So the fact that FM modulation is involved in not the issue at all. The issue is improper reference of flutter in analog systems as jitter and attempting to equate them as far as audibility. As I explain in that post in gory details, what looks on paper to be the same, is not so in practice. To use your analogy in reverse, they do NOT walk and talk like a duck. They just look that way smile.gif. To use such broad brush would mean that we would treat airplane and bicycle tires the same. Pretty sure no one would consider that proper even though they are both round.

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #51 of 119 Old 04-28-2014, 10:02 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,381
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 747 Post(s)
Liked: 1161
Quote:
Originally Posted by amirm View Post

Quote:
Originally Posted by arnyk View Post

If I correct Amir's erroneous plot (my work is hasty and therefore crude- IMO its up to him to do it right! ) I come up with this:


I would be happy to find any mistakes in my graph but I am puzzled as to what you are doing above.

I added the 20 dB correction due to the use of a 10x higher carrier frequency as described in this post: http://www.avsforum.com/t/1527897/any-sound-degradation-from-using-a-3-5mm-to-dual-rca-cable/30#post_24656713

There is actually a 12x difference between a 1 KHz carrier frequency as used in the Linn measurements and the 12 KHz carrier as used in the AVR measurements so the more precisely correct adjustment is 21.5 dB. But given the approximate nature of my artwork 20 dB seems close enough to make the point.
Quote:
Looks like you pulled down the AVR measurements to -110 db which is not correct.

Again as I explained above with a worked out example in post http://www.avsforum.com/t/1527897/any-sound-degradation-from-using-a-3-5mm-to-dual-rca-cable/30#post_24656713, running a jitter test with a different test frequency makes the sidebands change size given the same % of FM deviation. My example used 0.1% deviation, to help you remember.

To further clarify this issue. If one plays a test record with a 1 KHz tone on a turntable with 0.1% jitter, flutter, wow call it whatever you want to, the deviation given in Hz will be 1 Hz. If one plays a test record with a 10 KHz tone on a turntable with 0.1% jitter, flutter, wow call it what you want to, the deviation given in Hz will be 10 Hz.

According to http://en.wikipedia.org/wiki/Frequency_modulation The modulation index for the 1 KHz carrier modulated 0.1% with with a 60 Hz tone is the deviation (1 Hz) divided by the modulating frequency which 1/60 or 0.0166 . The modulation index for the 10 KHz carrier modulated 0.1% (10 Hz) with with a 60 Hz tone is 10/60 or 0.166 .

These are very small Modulation Indices and for small modulation indices the amplitude of the first sideband is approximated by the Modulation Index divided by 2. This approximated estimates the first sideband of the 1 KHz test at 0.008 and that of the 10 KHz test at 0.08 In dB that is -42 dB and -22 dB which agrees pretty well with the results I published in my previous post on this topic: http://www.avsforum.com/t/1527897/any-sound-degradation-from-using-a-3-5mm-to-dual-rca-cable/30#post_24656713 .


If you want to put two tests made with different frequency test tones on the same piece of graph paper, you have to adjust the amplitude of the sidebands in one test or the other to compensate for the differences in the frequencies of the test tones. I arbitrarily chose to use the coordinate system of the AVR tests.

If memory serves this issue has been covered in any number of papers that have been cited in your posts, Amir. I'm pretty sure without rereading it that it is covered in Benjamin and Gannon, for example.

Tell you what Amir, if you promise to pay me $10 for each paper that you have posted quotes from that covers this issue, I'll not only correct your graphic, but I'll correct your reading of those papers! ;-)
arnyk is offline  
post #52 of 119 Old 04-28-2014, 10:15 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,381
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 747 Post(s)
Liked: 1161
Quote:
Originally Posted by David Susilo View Post

Quote:
Originally Posted by amirm View Post

i-zCFzBVN-L.png

Hmmmm, I do remember being EXTREMELY adamant in saying that just because it's digital it doesn't mean it won't contain any jitter.

The presence of jitter in a digital signal is a minor inconvenience in a well-designed system. Digital audio gear that reclocks the digital signal before conversion to analog is as common as CD players (which is to say very common) because all CD players reclock the digital signal that is read off of the disc and have to do it well to sound good at all. That's one of the advantages of digital signals over analog signals. Its pretty easy to clean them up and make them almost perfect when everr they get a little soiled in handling.

HDMI audio signals that have passed over a HDMI cable have an inherent source of jitter in that the actual audio information is transmitted in packets that are interleaved with the digital video signal. I seem to recall that the convention is to transmit one audio packet with every scan line. Therefore they are not received in a continuous stream and have to be buffered and reclocked. Normally, buffering and reclocking is a good opportunity to reduce jitter to any desired low level that is desired.

Whatever performance level that we see in mainstream AVRs would thus seem to be completely intentional. It is my understanding that there are just a few third party suppliers of HDMI decoding chips, so this function is not fully under the control of the AVR manufacturers. They have to take what they can buy.
arnyk is offline  
post #53 of 119 Old 04-28-2014, 10:17 AM
 
gazoink's Avatar
 
Join Date: Apr 2014
Posts: 68
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 16
Quote:
Originally Posted by amirm View Post


What is unknown to us and everybody else is what you originally said: "scape flutter." Note lack of "r" in there. Sounds like you meant scrape flutter in which case I mentioned we know what that is. Please read my response to you carefully and note my use of the term "scrape" vs your "scape."

Scrape.  Sorry.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  

 

How many times to I need to write it on the black board before I can go out for recess? 

gazoink is offline  
post #54 of 119 Old 04-28-2014, 10:27 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,381
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 747 Post(s)
Liked: 1161
Quote:
Originally Posted by gazoink View Post

Quote:
Originally Posted by amirm View Post

What is unknown to us and everybody else is what you originally said: "scape flutter." Note lack of "r" in there. Sounds like you meant scrape flutter in which case I mentioned we know what that is. Please read my response to you carefully and note my use of the term "scrape" vs your "scape."
Scrape.  Sorry.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  

How many times to I need to write it on the black board before I can go out for recess? 

Point of order. Anybody who is familiar with analog tape technology is familiar with scrape flutter. I actually and quite without thinking read "scape flutter" as "scrape flutter". I believe that the first tape machine I ever bought that had a scrape flutter filter was either a Sony 355 purchased in 1967 or a Revox A77 purchased in 1969. In either case the flutter filter was an idler. It rested on the tape and reduced longitudinal oscillation. If memory serves the scrape flutter idler in the 355 had a sleeve bearing and the one in the A77 was a Swiss-made ball bearing.

http://en.wikipedia.org/wiki/Wow_and_flutter_measurement

"High-frequency flutter, above 100 Hz, can sometimes result from tape vibrating as it passes over a head, as a result of rapidly interacting stretching in the tape and stiction at the head. This is termed 'scrape flutter'. It adds a roughness to the sound that is not typical of wow & flutter, and damping devices or heavy rollers sometimes employed on professional tape machines to prevent it. Scrape flutter measurement requires special techniques, often using a 10 kHz tone."

I find the use of the word roughness to be both descriptive and ironic because the great pshychoacousticians Zwicker and Fastl characterize FM distortion of this kind as "roughness". IME that is what can easily come to mind when one hears it.

One important point being that scrape flutter can easily be at the same frequencies as clock jitter in digital. In a similar fashion some direct drive LP turntables have flutter in the 200 Hz range and up due to cogging by the many poles in their drive motors and the relatively low speed as which these motors operate (0.555 rpm)
arnyk is offline  
post #55 of 119 Old 04-28-2014, 01:42 PM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,078
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 750 Post(s)
Liked: 434
Quote:
Originally Posted by gazoink View Post

Scrape.  Sorry.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  Scrape.  

How many times to I need to write it on the black board before I can go out for recess? 
smile.gif

You can go to recess now if you don't keep saying we have never heard of analog tape and its distortions. You are not the only one that was into music before age of digital. Here is my current reel-to-reel:

i-CnTjkdn-XL.jpg

Which by the way, sounds incredible despite specs/measurements that say it can't!

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #56 of 119 Old 04-28-2014, 02:04 PM
AVS Addicted Member
 
Ratman's Avatar
 
Join Date: May 2002
Location: Collingswood, N.J.
Posts: 14,445
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 160 Post(s)
Liked: 285
That tree is dead. tongue.gif
Ratman is offline  
post #57 of 119 Old 04-28-2014, 02:22 PM
AVS Special Member
 
Frank Derks's Avatar
 
Join Date: Jul 2002
Location: Region A,B,C
Posts: 1,891
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 98 Post(s)
Liked: 89
Must be his bad taste in music or it sounds awful.

http://www.all-science-fair-projects.com/print_project_1301_143

smile.gif
Frank Derks is online now  
post #58 of 119 Old 04-28-2014, 02:26 PM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 14,381
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 747 Post(s)
Liked: 1161
Quote:
Originally Posted by Ratman View Post

That tree is dead. tongue.gif

Not only that, but showing a current technology system and using that to support the idea that

"You are not the only one that was into music before age of digital. Here is my current reel-to-reel:"

Is IMO a gigantic logical disconnect. AFAIK there is no apparent logical connection between the claim from "before the age of digital" and the evidence which is obviously from the age of LCD.

Of course we have been just been dealing with a logical disconnect which may be at least just as big with the superposition of jitter tests taken using test signals that had vastly different frequencies without appropriate rescaling of the results.
arnyk is offline  
post #59 of 119 Old 04-28-2014, 02:53 PM
AVS Addicted Member
 
amirm's Avatar
 
Join Date: Jan 2002
Location: Washington State
Posts: 18,078
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 750 Post(s)
Liked: 434
Quote:
Originally Posted by Ratman View Post

That tree is dead. tongue.gif
You know in the five years that has been there, you are the only one to say that. Everyone else knows it is decoration and came that way!

Amir
Founder,
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"Insist on Quality Engineering"

amirm is offline  
post #60 of 119 Old 04-28-2014, 03:28 PM
AVS Addicted Member
 
Ratman's Avatar
 
Join Date: May 2002
Location: Collingswood, N.J.
Posts: 14,445
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 160 Post(s)
Liked: 285
Quote:
Originally Posted by amirm View Post

You know in the five years that has been there, you are the only one to say that. Everyone else knows it is decoration and came that way!
I did not know that! Maybe they didn't want to hurt your feelings or embarrass you. biggrin.gif

Kind of like "The Dead Parrot" routine from Monty Python.
David Susilo likes this.
Ratman is offline  
Reply Audio theory, Setup and Chat

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off