"Official" Audyssey thread (FAQ in post #1) - Page 1599

Audioguy, can I just chime in here? Roger and Sanjay are giving great advice but you still seem a little unsure about DSX/Wides (forgive me if I am wrong). What both R & S are saying is that if you have a proper pair of side surrounds and a proper pair of rear surrounds, and the side surrounds are moved somewhat *forwards* from the usual 90 degree position, then you will 'fill in' the gap between the fronts and the rears nicely and this may well mean that you don't need Wides at all. As Sanjay has said, the side surrounds will phantom image to some extent to the rear of their actual position and this arrangement of the fronts, side surrounds and rear surrounds will give you a terrific overall envelopment. As Roger said, if you want a slightly wider front soundstage, move your front L & R speakers a little further apart.

I was a big fan of DSX (for height channels - I have no room for wides) but more recently I have moved away from it and now use PLIIz for my Height channels. The reason was that, in the end analysis, I disliked the way that DSX actually works and the way in which it generates the 'content'. It does things to the regular 5/7.1 soundstage that is not only moving away from the Director and Mixer's intent but which also upsets the overall soundstage. It was Roger, in fact, who made me realise this in a discussion he and I had and he told me what to listen for and how to listen. This is just my opinion of course- there are others who swear by DSX and that is fine.

I have a "110 sound screen. My 3 Tower speakers are behind the screen. It is electric and I also have a "50 plasma ceiling mounted and use that for tv viewing. I use the projector/screen for blurays and sports. When running Audyssey with my A100 should I have the screen up or down or does it not matter? Screen is perforated. I did have screen down the last time I ran Audyssey.

I lower my seat back also on the chairs Im measuring to keep the sound from reflecting off the seatbacks. If you cant lower them, then be sure not to put the mic too close to the seatback to avoid this.


I would recommend raising the mic above the couch back to avoid reflections from the couch back that could interfere with the measurements












IMHO that is not a good idea. reflections

I have a sealed room with plenty of space behind the TV, and also behind the couch at my main listening position. So I will duck behind the TV or the couch while raising the remote in order to press enter and start an Audyssey measurement. After the subwoofer is tested at a measuring position, I'll poke my head up to check the TV screen and make sure there hasn't been an error. Lather rinse repeat for all 8 measuring positions...

That is true, but thank goodness I never listen to my system at the reference level setting on the master volume control. A level of 5 dB below reference level sounds loud but just about right for an action movie.

Primarily what I use the dialnorm information for is to make an equal level comparison of a DD soundtrack and a DTS soundtrack. Kind of tricky to do that if you do not know where the starting point is. THX makes that comparison more difficult.

Here are a few DD / DTS comparisons that I have made in the past. There is quite a span in reference level if dialnorm is not taken into consideration. In my system there is an 8 dB difference in DD/DTS playback level in War of the Worlds due to dialnorm, and no difference in PofC-1.

Also note that PofC-1 uses a Surround Level of -6 dB. Is that something a DD Decoder handles in the AVR sound matrix (AKA surround level is played back a bit lower than usual)?


Pirates of the Caribbean-1

C-Level = -3dB, Surround-Level = -6 dB, Dialnorm = -31



Master and Commander

C-Level = -3 dB, Surround Level = -3 dB, Dialnorm = -27



War of the Worlds

C-Level = -3 dB, Surround Level = -3 dB, Dialnorm = -23

If it was sealed after you got in, at least you have Internet connection, ...that's good, coz we can communicate! JK!!

It's a good job you have stacked 3 of those subwoofers, because you'd not get anywhere near -5dB otherwise.

It's not PERMANENTLY sealed
Actually the cable modem and router are in that room, so I could connect my AVR and other home theater components via Ethernet.

Thank you. I much appreciate your contribution.

Good!


Yes.


Neo:X or PLIIx. No harm in trying DSX but it will shock you.

Exactly. It just means the offset relative reference, not that you have to play it at ref.


Are you saying that the Dialnorm value is -23?


I don't understand how you arrive at levels for center and surrounds. Relative to what? The various channel are all recorded into the 5.1 bitstream at the same relative levels as in the source master.

I do not disagree with you. Not to mention that those passive ported subwoofers require the use of a HP filter on the 20 Hz area. I have 4 of those subwoofers, but no place in the room to position the last one where it makes a difference. At least they do not weigh 150 pounds like the higher performance subwoofers do.

Now I could upgrade that subwoofer system, but that would only be to dig a bit deeper at the low end. However, my "room" is open to the rest of the house, and most of the time I do not play the system that loud. So why spend money and give up room real estate to dig deeper when I will not notice a difference the vast majority of the time?

Do I need to dig deeper than I do now for music? No.

For television programs? No.

For movies? Most of the time, no.

For War of the Worlds, yes the dialnorm value is -23. My receiver and my PC report the same DN value.





I read those levels off the mixer in my PC. PofC uses a different Slevel value that most other DVD's, so perhaps that is just a meta data report of encode information. I was able to copy the information, so here is the info that is available to me.


Pirates of the Caribbean - 1

Input format: MPEG Program Stream - 48000
User format: PCM Float - 0
Output format: PCM Float 3/2.1 (5.1) 48000

Decoding chain:
(MPEG Program Stream - 48000) -> Demux -> (AC3 - 48000) -> Decoder -> (Linear PCM 3/2.1 (5.1) 48000) -> Processor -> (PCM Float 3/2.1 (5.1) 48000) -> Dejitter -> (PCM Float 3/2.1 (5.1) 48000)

Filters info (in order of processing):

Demux:
-

Decoder:
Stream format: AC3 3/2.1 (5.1) 48000Hz
Bitstream type: byte stream
Frame size: 1792
Samples: 1536
Bitrate: 448kbps
SPDIF stream type: 0x1
Frame interval: 1792
Actual bitrate: 448kbps
AC3
speakers: 3/2.1 (5.1)
sample rate: 48000Hz
bitrate: 448kbps
stream: 8 bit
frame size: 1792 bytes
nsamples: 1536
bsid: 6
clev: -3.0dB (0.7071)
slev: -6.0dB (0.5000)
dialnorm: -31dB
bandwidth: 14kHz/20kHz

Processor:
(Linear PCM 3/2.1 (5.1) 48000) -> Input levels -> (Linear PCM 3/2.1 (5.1) 48000) -> Input cache -> (Linear PCM 3/2.1 (5.1) 48000) -> SRC -> (Linear PCM 3/2.1 (5.1) 48000) -> Mixer -> (Linear PCM 3/2.1 (5.1) 48000) -> Bass redirection -> (Linear PCM 3/2.1 (5.1) 48000) -> Equalizer -> (Linear PCM 3/2.1 (5.1) 48000) -> Dither -> (Linear PCM 3/2.1 (5.1) 48000) -> AGC -> (Linear PCM 3/2.1 (5.1) 48000) -> Delay -> (Linear PCM 3/2.1 (5.1) 48000) -> Output cache -> (Linear PCM 3/2.1 (5.1) 48000) -> Output levels -> (Linear PCM 3/2.1 (5.1) 48000) -> Linear->PCM converter -> (PCM Float 3/2.1 (5.1) 48000)

Dejitter:
-

While it is your choice what you do in your room, I don't agree with your opinion that replacing your subwoofers with something that will go below 18Hz wouldn't make a noticeable difference. If you have never experienced deep authoritive bass then you wouldn't miss it, but it does make a very big and very noticeable difference.

It does not have to be expensive. I'm set to build a DIY subwoofer that will easily outperform a 'manufactured' subwoofer at around 4 times the price. Once I've got the best performance from it, I will then add another.

I'd expect a decent subwoofer to be something more like 100lbs, especially as a good quality drive unit will generally weigh up to 40lb or more. Also, it doesn't take a genious to work out that a good solid cabinet will add a lot to the weight - I'm sure I don't need to point out the benefits of that.

OK, I get it now. Downmix to stereo surround is different than downmix to stereo. Applies to equipment connected to AVR, including my PC.


-----------------


Downmixing

Downmixing allows a multichannel program to be reproduced over fewer speaker channels than for which the program is optimally intended. Simply put, downmixing allows consumers to enjoy a 5.1 channel broadcast regardless of how many speakers they have.

Set-top boxes, used for the reception of terrestrial, cable, or satellite, typically offer an analog mono signal modulated on the Channel 3/4 output, a line-level analog stereo signal and an optical or coaxial digital output. The analog stereo output is a downmixed version of the decoded Dolby Digital bitstream while the digital output delivers the Dolby Digital bitstream to a downstream decoder.

In each of these devices, the analog stereo output is one of two different stereo downmixes. One type is a surround-compatible downmix (left-total/right-total, or Lt/Rt) of the multichannel source program suitable for Dolby Surround Pro Logic or other matrix decoding. The other type is a simple stereo downmix (called a left-only/right-only, or Lo/Ro) suitable for playback on a two-channel stereo system or on headphones, and from which a mono signal is derived for use by an RF re-modulator.

The only difference between the downmixes is how the surround channels are handled. The Lt/Rt downmix sums the surround channels, attenuates them 3 dB (i.e. multiply by 0.707) and adds them out-of-phase to the left channel and in-phase to the right channel. This allows a Pro Logic home theater decoder to produce L/C/R/S channels when connected to a stereo set-top box or DTV receiver. Conversely, the Lo/Ro downmix adds the right and left surround channels discretely to the left and right speaker channels. This preserves the stereo separation for stereo-only monitoring and produces a mono-compatible signal. Lt/Rt is the default selection in all consumer decoders with the exception that the mono signal feeding the RF re-modulator output is derived from a Lo/Ro downmix.

The formula for Lt/Rt compatible and Lo/Ro stereo downmixes are:

Lt = L + (0.707*C) - (0.707*Ls) - (0.707*Rs)

Rt = R + (0.707*C) + (0.707*Ls) + (0.707*Rs)

Lo = L + (clev*C) + (slev*Ls)

Ro = R + (clev*C) + (slev*Rs)

With Lo/Ro you can see that there are separate metadata parameters included in the downmix formula. The metadata parameters clev (center level) and slev (surround level) default to 0.707 (i.e. -3dB just like in Lt/Rt) but can be adjusted to fine-tune the stereo downmix.

What about the LFE channel? Well, it is simply discarded. Be very careful about audio that is only in the LFE channel for the logical reason that not all consumers will hear it.

I have looked at enough spectrum waterfalls of movies to have a good feel what is on most of them. If the infra is not on the recording, it won't be reproduced by the subwoofer(s). I get kind of tired of hearing that for movie XYZ the bass is great, but the movie is not. Even a movie like Master and Commander does not "require" a super deep low end FR.

I know how everything adds up. Heck if I add up the weight of my passive subwoofers, amplifiers and subwoofer crossover/EQ unit I am probably over 150 pounds. It is just so much easier to move a 40 pound subwoofer X 3 around than a 150 pound unit with the amplifier built into the cabinet.

Size is more of an issue to me. I have seen plenty of those ICBM type of subwoofers, refrigerator size subwoofers and wega watt sealed subwoofers. There are subwoofers, and there are subwoofers. I just am not going to go "off the deep end" when 99.9 % of the time there is no real need for it (although I have been tempted to do so).

JPC, if you're happy with what you have, so be it and count yourself lucky. Upgradeitis is one heck of an expensive disease.

In my case though, watching the 'pod emerging' scene from WOTW was enough to justify the Seaton Submersive HP. All I can say is "WOW!" It just made that scene (and other scenes with that kind of content) so much more involving and impressive. The impact of the low and ultra low end is so visceral, it evokes responses that are more... basic/primitive? As in the opposite of cerebral. The opposite of, "yes, there's definitely more air and separation around the cymbal strikes, and a refined clarity to the highest notes on that violin". It's more of a "Holy S##t!!! That's ridiculously AWESOME!!!"



Max

Well, I've watched/heard enough movies to know that a Subwoofer capable of going down to at least 10Hz is far better than one that is only capable of reaching 18Hz. I imagine that you get tired of hearing it, because you have such a weak argument against it.

You are right, Master and Commander doesn't 'require' super deep low bass, but it is definitely much better with a system that is capable of the full frequency range on the soundtrack. The broadside cannons go down below 10Hz, for example, so you are not experiencing the full impact of them.

Adding the weight of your individual subwoofers and the external amps does not equal a single well built subwoofer just because they weigh about the same!!

The subs I have planned aren't going to be huge, but with each driver weighing in at around 50lbs each, they are no doubt going to be pretty heavy - even though I'll be using external amps. I don't intend to move the Subwoofers around once they are positioned though, which I believe is quite normal for most Home Cinema systems. I honestly wasn't aware that a light-weight portable subwoofer was a good thing - and I don't think I am alone on that one.

Hahaha - a great analysis. Surely everyone here seeks that Holy $h1t moment!?

He alludes to some unintended bass here -

I don't think I am making a case for any subwoofer at all. I just said what I can reproduce with some evidence to back it up.

If you want to argue, then 3 Hz is better than 10 Hz. Do you want to argue against that?


http://www.youtube.com/watch?v=7pKyh...UNc3YHkTCD9HCU





Saying your subwoofers are not being "huge" is meaningless on this forum. That could mean anything at all.

Not sure of your sarcastic "logic" relating subwoofer weight and my comments about lugging speakers around. I have a pair of mains that weight 90 pounds each, and they are no fun to move. So they are just connected to my PC for the moment.

I have considered updating the drivers in these subwoofers, but then I say why bother.

In addition, "Home Cinema systems" is a vague term. I am talking about a living room system, not a full blown home theater setup with speakers hidden behind a screen. If you knew how the rest of my system setup, you would have a hissy fit. That's why I give limited information to Marcus. Prior AVS experience!






Are you sure about that 10 HZ content, or is that an opinion?

Refer to my next post for my opinion.

Yes hopefully he will, because if it wasn't supposed to be there then surely it would be removed as part of the mixing process. I don't see why anything would be there unintentionally, unless it's an error.

That's one reason I run my "large" mains as large. My subwoofer "crosses over" to my mains at a nominal 50 hz at the high end, and at 15 Hz at the low end (AKA mains produce more infra than subwoofer below 15 Hz). Granted, the main speakers roll off in my system so main infra is not at a super high SPL level. But the same thing happens in a mixing studio or movie theater.



Here is a waterfall of Master and Commander DVD Opening Salvo sequence. Left is LFE. Right is L, C, and R channels mixed together. Do you see much infra on the LFE channel? The bottom line is Master and Commander rolls off from 30 Hz on down like a lot of other movies do. There is infra shown at times on the main channels that the mixer could have never heard or felt, but is it loud enough to notice at a typical "normal" home playback volume with bass redirection in use?

RED color means loud.







Here is an RTA of the same sequence. Peak hold function was used. Purple is the LFE channel alone. Red is the L, C and R channels mixed together. Green is the LFE, L, C, and R channels mixed together. Master and Commander also has an estimated peak SPL level of about 118 dB SPL in this sequence with the usual assumptions about reference level.

Note that the 80 to 120 Hz area on the combined main channels is quite loud relative to 30 Hz on the LFE channel.

No, you are saying you don't feel there is any point in having a subwoofer that can reproduce frequencies below 18Hz. You claim that going lower does not interest you, which is fine, but suggesting that it wouldn't be an improvement is just your opinion. This whole discussion has stemmed from you trying to pass off the benefits of bass that your subwoofers are not capable of.


I'm not going to argue against that, because yes, the lower the better I say. It is you who is arguing that anything below 18Hz is not worthwhile. I sold my commercially manufactured subwoofers that were performing very well down to 10Hz. Using the money from just one of them, I will be replacing them with two DIY subwoofers that will perform way better and go much deeper.


I can't give exact sizes yet, as the TSP's are not available for the drivers I intend to use. I have a small room and not really a lot of space to play with, which is why I am saying they will not be huge.


That isn't really anything to do with the discussion about the weight and build quality of a subwoofer.


That is your decision, based on your opinion.


It may be a vague term, but if it's a dedicated room or a setup in a living room, who moves their equipment around often enough to care about the weight. The whole point here is that a good quality driver for a subwoofer is generally quite heavy compared to cheaper, older or lower performance drivers. Good solid cabinets also tend to be quit heavy.

I don't have any idea why I would have a hissy fit about the rest of your system. Now who's being vague, again!! I honestly don't care one bit about the rest of your system. In fact, I cringe at the thought of it and I'm thankful for what I have.

Am I sure about what 10Hz content? On Master and Commander? I've seen the measurements for it - so unless they are falsified in some way, then yes. There are also other parts in the movie that easily get down to 12Hz at higher volumes.

I have primarily discussed one speaker that I have used to fill in FR dips at the LP in an unconventional manner (Geddes theory). I have really not discussed the balance of the system in any detail except for some "crossover" frequencies.

You know that I am psychic, so I already know what the response will be before I post much detail about my full system. I just do not know who will have the big hissy fit. No need for that on this thread.

You can deny it if you like, which just proves you have a lot to hide.


Then you should already know where to look. It's one thing to look at a graph, but actually experiencing it on a system that is capable of reproducing it is very different, but you wouldn't know about that. It's not just that movie either, so your argument is still pointless.

Now, if you'll excuse me, I have the rest of my weekend to do something constructive with. I'm sure everyone else is getting tired of the bickering as well.

J_Palmer_Cass & those engaging in the discussion with him - Might i kindly request you take this discussion to a separate thread? This thread is about Audyssey, and it's getting tiresome to have to wade through pages of discussion about stuff not really related to Audyssey. Thanks!