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In Reply to: SACD vs DVD-A article posted by Rod Paine on August 17, 2004 at 14:02:03:
Hi everyone!
I would like to thank Eric for invitation to this thread, It is always good to discuss anything with knowledgeable people. I would like to explain some parts of the article and logical approach to use different modes. Now after discussions around the world in different forums, I got even more information, confirming the results. Let's try to do it step-by-step. I have no problem to admit if I was wrong somewhere.
Dan Banquer: you are absolutely right, FIR Brickwall filters don't shift phase, I even made such experiment by myself before publishing of the article, using marqueee tool in Adobe Audition 1.5 - just to compare the the FFT graphs for the same signal with HF and without, cutted by marquee tool. Where in the article is the problem concerning your statement?
Dave Kingsland:
[i]they talk about Griesinger's observation that many SACDs and DVD-As don't contain the "advertised" ultrasonic frequency content.[/i]
Not many, all of them, used in experiment.
[i]Two of the examples they pick are the James Taylor Hourglass SACD and Steely Dan Two Against Nature DVD-A. Perhaps they didn't notice, but these are 24/44.1 and 24/48 PCM recordings, respectively.[/i]
24/44.1 and 24/48 PCM recordings - do you mean the original studio recordings? It was a reason to pick up those two recordings. Steely Dan was used in the previous experiment, is was a good point to compare it, and Taylor demonstrated some interesting difference in measurements - a bit later about them.
[i]Given that Two Against Nature is a 48k PCM recording and the DVD-A tracks are 24/48 MLP ... That extra frequency content could only be produced by some sort of non-linear processing in their playback chain because it isn't on the disc. But they fail to recognize this.[/i]
I have this disk (actually I buy only DVD-A Advanced resolution after some mistakes) Steely Dan Two against Nature and it is "Advanced resolution" DVD-A with "This disk playes 4 ways: Advanced resolution Stereo - Advanced resolution 6 channel surround sound ...", it means Giant Records give us an idea that it has 24/96 recordings. I REALLY doubt that Giant Records provides intentionally falsified statement on the disk, if the record is in 24/48 regular resolution.
Concerning Taylor, a bit later, I have some very interesting information.
[i]Unfortunately, their conclusion is exactly backwards because the disc's content is only 24/48 MLP.[/i]
If you have any information concerning additional ultrasonic imagas, created in the process of THX Music post processing, I would love to have it and immidiately admit that the assumption was wrong. Or I would like to have the confirmation that on this Advanced resolution DVD-A content is in 24/48 MLP.
Everywhere (AFAIK) "Advanced Resolution" meant 24/96, if it is 24/48 MPL, someone would sue Giant Records for the fraud ...
Here is the link how Advanced resolution recordings created http://www.soundonsound.com/sos/aug03/articles/steelydan.htm
http://www.audaud.com/audaud/MAR02/HIRES/hires1MAR02.html#steel
[i]If they had any question at this point about where that ultrasonic content was coming from, it should have been cleared up after they plotted the data from the Hourglass SACD. If you look at the last plot of the Hourglass multichannel data taken directly from the DV-47Ai player, you'll see exactly what you should expect from PCM data converted to DSD: signal content out to a brick wall cutoff at fs/2 followed by DSD's rising noise floor.[/i]
What is interesting, there is NO PCM to DSD conversion in 47Ai ... no such device exists. I will explain what happens with the Taylor a bit later again :) Did you mean DSD->PCM conversion? In 47Ai DSD stream processed through the analog filters in PCM1738 DACs, used for such purpose, for front channels, and through DSD1702 DACs for surround channels.
[i]The most likely cause is some sort of multichannel processing mode (e.g. THX, dynamic range compression) engaged in the receiver that they forgot to turn off. They even allude to the fact that THX processing is enabled.[/i] Do doubts dynamic compression was off, it is off all the time in my receiver. I used THX Music mode intentionally, this is the best mode for me to listen to the multi-channel music, and I was wondering why it is that good. In this mode I had been able to check front channels and compare the results with Direct mode in the receiver. People, who read the article, will also listen to the multi-channel sources in the best mode, in this case in THX mode. The reason to use receiver was that the path for SACD signals and PCM signals, except of DSD->PCM conversion in SM5816A, is the same - this allows to make the comparison better. The goal was to compare DVD-A and SACD in the best possible listening modes.
[i] But one thing you can be absolutely sure of is that frequency content is not on the disc, and unfortunately this exactly the conclusion they reached.[/i] Prove it. We will sue Giant Records for million of $ together with you in this case, and share the profit :) Why don't you talk here about another SACD, Diane Krall "When I look in your eyes", which gave almost the same results as Steely Dan DVD-A?
Sir, I admit the possibility of my mistake, why are you so sure that you can't make any?
[i]Incidentally, you can also see the same signature in the multichannel data from the DSTOM and Krall discs - what looks like extraneous content in the 22-32 KHz range. The only difference is that these examples have wider bandwidth to begin with because they're not sourced from lower-res PCM, and thus there isn't a clear notch in the data from the brick wall cutoff.[/i]
Take a look here, I had made the spectral comparison, all samples are from 47Ai, no THX processing in this case:
http://members.cox.net/alex_lat/Tests/Taylor-2.PNG
It means your theory concerning non-linearity in the DSP processing of receiver is not correct.
[i]As if the cutoff at 22 KHz is due to some sort of filtering during playback.[/i] You hit the nail on the head! It looks as I'd found the reason of such sharp cut-off in the process of playback comparing the different modes of DSD decoder CXD2753 ... http://members.cox.net/alex_lat/Tests/RFSACD.PNG http://www.avsforum.com/avs-vb/showthread.php?postid=4216351#post4216351
Below you will find the information, explaining the difference on Taylor SACD.
[i]Funny that playback on the 47Ai standalone and playback on the 49TXi via iLink were so different that even after matching levels, capturing them with a sound card, and playing them back on the computer they could still identify the difference 19 out of 19 times in an ABX test. Shouldn't that raise a few eyebrows, maybe hint that there may be some extra processing going on in the 49TXi?[/i]
Don't hurry to raise eyesbrow :) Lynx L22 is a good device to do such things, here are the results of it's measurements:
http://www.photosyndikat.de/RMAAtests/Lynx L22_24-96.htm
The difference IMO is in the ultrasonic images, but not separated from the audible contest, here is the scientific research, confirming it (the full article in in pdf file in the right upper corner of link)
http://jn.physiology.org/cgi/content/abstract/83/6/3548
[i]Naturally, because of their apparent failure to understand their own source material and playback setup, the conclusions they reach range from suspect to outright wrong.[/i]
Dave, you are a knowledgeable person, but I respectfully disagree :)P.S. I would like to thank Cristine Tham, presented here, for the perfect article!
Follow Ups:
and I must commend you on your enthusiasm.one question i have is that your graphs consistently show what appears to be higher relative dynamics in the m-ch versions compared to the stereo versions and you seem to be implying that in your text.
can you confirm this is so? have you also compared the difference between Maximum RMS - Average RMS across the various recordings (using the statistics function of adobe audition) and do they also support the hypothesis of higher relative dynamics?
i've always suspected this to be the case, as the stereo track is often the original mix which may have been dynamically compressed and the m-ch track being a remastered mix may be more dynamic. it would be good if you can confirm that. Dark Side of the Moon is a classic example - i can easily hear with my ears that the m-ch track is more dynamic, no need for any measurements! :-)
in terms of whether THX Music Mode adds ultrasonics or not, it's hard to say, without knowing exactly how THX post processing is implemented. to avoid criticisms like these, it's always better to do these kind of measurements in as "vanilla" a mode as possible, with all extraneous processing turned off.
*if* the original masters are at 44.1 or 48 kHz sampling, then the ultrasonics in the m-ch tracks can also be explained by processing done during the surround remix (for example, digital reverb).
Hi Christine,
Thank you for your kind words. Sorry for the late response, a lot of things to do.
Here are some examples of statistics:
Here are non-amplified samples of Steely Dan (song #3):
Multi-channel (49TXi, THX Music mode, multi-channel tracks):
Left Right
Min Sample Value: -24567.84 -28009.15
Max Sample Value: 25585.62 26199.07
Peak Amplitude: -2.15 dB -1.36 dB
Possibly Clipped: 0 0
DC Offset: 0 0
Minimum RMS Power: -130.81 dB -132.59 dB
Maximum RMS Power: -7.39 dB -7.13 dB
Average RMS Power: -17.53 dB -17.68 dB
Total RMS Power: -16.31 dB -16.44 dB
Actual Bit Depth: 24 Bits 24 BitsUsing RMS Window of 50 ms
SACD Direct mode (49TXi) - the same path, stereo tracks:
Left Right
Min Sample Value: -29268.24 -23927.14
Max Sample Value: 30109.54 24818.42
Peak Amplitude: -.73 dB -2.41 dB
Possibly Clipped: 0 0
DC Offset: 0 0
Minimum RMS Power: -98.55 dB -99.78 dB
Maximum RMS Power: -9.34 dB -10.59 dB
Average RMS Power: -19.43 dB -20.72 dB
Total RMS Power: -18.57 dB -19.91 dB
Actual Bit Depth: 24 Bits 24 BitsUsing RMS Window of 50 ms
The Dark Side of the Moon, song #7, analog output of 49TXi,
recorder to Lynx L22 through analog inputs:
THX Multi-channel mode:
Left Right
Min Sample Value: -29205.91 -27668.32
Max Sample Value: 26756.17 26553.34
Peak Amplitude: -1 dB -1.47 dB
Possibly Clipped: 0 0
DC Offset: 0 0
Minimum RMS Power: -138.54 dB -116.37 dB
Maximum RMS Power: -6.18 dB -6.61 dB
Average RMS Power: -16.68 dB -16.18 dB
Total RMS Power: -15.71 dB -15.36 dB
Actual Bit Depth: 24 Bits 24 BitsUsing RMS Window of 50 ms
Direct SACD mode:
Left Right
Min Sample Value: -29449.83 -25638.68
Max Sample Value: 30058.36 26596.29
Peak Amplitude: -.75 dB -1.81 dB
Possibly Clipped: 0 0
DC Offset: 0 0
Minimum RMS Power: -96.85 dB -98.03 dB
Maximum RMS Power: -7.02 dB -8.06 dB
Average RMS Power: -15.53 dB -15.74 dB
Total RMS Power: -14.82 dB -15.11 dB
Actual Bit Depth: 24 Bits 24 BitsUsing RMS Window of 50 ms
I absolutely agree with you concerning the original mix on stereo tracks, I read it concerning DSotM, for example.
We will try to find out is ultrasonic image added by THX Music processing (and I still really dount it, only one thing can add such ultrasonics - slow roll off in DF1706, as for example in Hi-Bit/Hi-sampling mode or Legato Pro).
Need to explore the schematics, will reply later.
I still think that even if the original masters were recorded at 24/48, in the process of multi-track remastering some artificial ultrasonics could be added to make the sounding more pleasurable, as an example - it could be done with Aural Activator or something similar. We will find out.
the lower dynamics on the stereo track of DSOTM is pretty shocking, isn't it?i wonder why? maybe it's just due to the tape's age - the LP sounds better in comparison.
It could be the age of the tape ...
My suggestion concerning so good results for multi-channel tracks is - they used the digital silence in the process of re-mastering between the tracks ... the real difference in DR between stereo and multi-channel tracks couldn't be THAT high ...
What do you think, Christine?
one question i have is that your graphs consistently show what appears to be higher relative dynamics in the m-ch versions compared to the stereo versions and you seem to be implying that in your text.
can you confirm this is so? have you also compared the difference between Maximum RMS - Average RMS across the various recordings (using the statistics function of adobe audition) and do they also support the hypothesis of higher relative dynamics?
Take a look at figure 6 in the article:
http://www.ixbt.com/dvd/sacd-dvd-a/fig6.png
The statistics you're interested in seem to indicate slightly greater dynamics from the stereo tracks (right hand side) but it's not clear whether the statistics are for a whole track or just a sample. I assume a whole track since it's clearly not just for the brief sample shown in the traces at the bottom.
*if* the original masters are at 44.1 or 48 kHz sampling, then the ultrasonics in the m-ch tracks can also be explained by processing done during the surround remix (for example, digital reverb).
Nope. Take a look again at Hourglass multichannel track data that Alex took from the outputs of the 47Ai:
http://www.ixbt.com/dvd/sacd-dvd-a/fig4.png
http://members.cox.net/alex_lat/Tests/Taylor-2.PNG
No unexpected ultrasonics are present except in the data taken from the 49TXi. I'm not sure how I could make this point any more clear...
Dave
i think i would prefer alex to provide the answers rather than make assumptions based on the graphs in his article.as you say, we really don't know what those statistics really represent (whole album, 1 track, or simply the waveform as depicted below the statistics).
in terms of the "fake" ultrasonics - that was how i initially read the graphs, but alex seems adamant that is not the case, so i am trying to prompt him to offer more explanation, just in case (for example) the graphs are wrongly labelled and he was comparing stereo against m-ch outputs.
i'm trying my best to give alex the benefit of any doubts and to understand his position. i found his writing style a bit difficult to comprehend, and i realise english is probably not his first language, so i'm willing to give him a chance. i know i hate it when people misread my articles, and then start criticizing them without even bothering to check that their criticisms are valid.
i'm trying my best to give alex the benefit of any doubts and to understand his position. i found his writing style a bit difficult to comprehend, and i realise english is probably not his first language, so i'm willing to give him a chance. i know i hate it when people misread my articles, and then start criticizing them without even bothering to check that their criticisms are valid.
Christine,
Why beat around the bush? Just tell me you think I'm an asshole for criticizing Alex's article. I deserve it.
I've been trying to hold this back, but I just can't anymore. The real problem here is that anyone with a sound card and web hosting space can take measurements and fancy themselves a technical writer. It used to be that technical articles carried some weight, because the authors typically had credentials and their work was reviewed by staff technical experts or industry/academic peers. But now the internet has become a vehicle for mass disinformation with far too many poorly researched articles that reach the wrong conclusions or make sweeping generalizations based either on bad assumptions or suspect/insufficient data. Technical articles should be held to higher standards than opinion pieces.
I think that you, Alex, and everybody else who publishes articles of this sort on the web need to be a lot more diligent in your work. It's simply irresponsible to just throw something out there as if it's an authoritative work and rely on the denizens of the internet to help counter/correct the errors in it after the fact. In my opinion, the review process is something that should take place *before* publication, and forums like this one are not the place to find qualified reviewers. I KNOW that I am not qualified to review your work or Alex's, so if I can find basic problems in the first reading then something is wrong. And I would like to continue educating myself using the internet as a souce of information, but how can I do that if I can't have at least some minimal trust in what I read?
I _really_ don't like getting involved in these discussions, but at some point people have to cut through the platitudes ("interesting artcle", "good job", etc.) and call a spade a spade. Otherwise, people who practice irresponsible journalism will continue to plant seeds of misinformation that spread like wildfire around the internet.
Anway, I've ranted enough and this is the end of the discussion for me. Feel free to have the last word and defend yourself as you see fit.
Dave
Dave,
I don't understand your emotions. We are here to learn, don't we?
I agree with you concerning the technical articles, but it is not one of them. Another point is - nothing wrong is in it - though we we have 2 choices - fraudulent (because no one warned about such possibility) additional ultrasonics in 49TXi (then it should be the same in 49TX and 59TXi) or existing on the disk ones. We don't know the truth yet, but we will find out. Without attention to this article from experts around the world and their help we would never do it.
This article had been reviewed (and discussed) many times - by technical experts in iXBT, the best Russian technical website and personally by Maxim Ladov, the director of RMAA project and editor of Home Theater and DVD plus Multimedia parts of iXBT. He is an author of many reviews as well.
I don't understand your emotions. We are here to learn, don't we?
What about the all the people who read your article and accept the conclusions it contains because they don't know enough to question your results? Have they learned anything? Your article has only added to the vast amount of misinformation being spread around on the web. The main reason why I got interested in the web 10 years ago was the potential to learn about new subjects and new research. But how can I really do that if a large percentage of the technical articles on the web are untrustworthy? Most of the time, readers are not knowledgeable enough to sort out the good from the bad. I can only do it in certain areas of certain subjects. The rest of the time, I'm relying on responsible journalistic practices not to misinform me.
I agree with you concerning the technical articles, but it is not one of them.
That is a cop-out excuse. You wrote a factual article, not an opinion piece. Your article presented data and analyses and your conclusions were presented as facts.
Another point is - nothing wrong is in it - though we we have 2 choices - fraudulent (because no one warned about such possibility) additional ultrasonics in 49TXi (then it should be the same in 49TX and 59TXi) or existing on the disk ones. We don't know the truth yet, but we will find out. Without attention to this article from experts around the world and their help we would never do it.
My point is that it shouldn't be up to casual readers in internet forums to inform you about the nature of your source data or point out issues with your test setup, and it certainly shouldn't happen AFTER the article is published.
What makes me so upset about this discussion is that you and Christine seem to be unconcerned about how many people are misinformed while you two try to make a name for yourselves as audio experts and journalists. I'm sorry, but I'm afraid I just can't have a level headed conversation with either of you about this.
Dave
Dave,I think you vastly overestimate the critical process involved in scientific and technical papers (I won't even mention journalists). Some fantastic misunterpretations have been published over the centuries, without anyone daring to verify or even question the results. I remember seing one book about this, but I can't find the title at the moment, but examples of scientific mistakes abound*.
The discussion that followed Alex's publication on this board is a very healthy one in my opinion, including your careful reading and subsequent discussions. Since he has the ability to correct, amend, or complement his article, the process is actually productive, including for readers who are not specialists, like me.
And, again, I think a lot of the problems raised could be prevented by some common methodology and procedures. This would also allow comparisons between different people and publications.
Cheers
Eric
* I do have one example in mind, though. One of the leading sociology books, Durkheim's Suicide, contained a major misunterpretation of some statistical data. That book was reviewed, published, and studied by thousands (if not tens of thousands) of students, teachers, researchers, and no one had noticed this mistake for about a century, until one guy actually double checked the tables in the book.
BTW, the book is still printed with the same mistake, and there's not even a mention of the article where this was discovered :)
Eric,I don't expect perfection, but there have to be some minimum standards in every field otherwise nobody can learn anything from the body of published works. The level of rigor varies by field. It's been quite high in the fields I have had the opportunity to publish or present work in. But rigor seems utterly missing in audio and garbage science has almost become the norm. A lot of the technical articles published in this field could use a disclaimer: "For entertainment purposes only", because that's all you're going to get out of them.
But even in the absence of standards, I still expect people to take responsibility for the accuracy and correctness of what they publish. I don't think Alex is willing to do that. I even question his motives for replying here and I have my doubts about his sincerity in wanting to resolve the issues raised by Dan, Frank, and myself. I think Alex is only interested in damage control and further, I expect that we will be able to revisit this article in 6 months and it will still be there without any resolution to these issues.
I admire your attempts to find some sort of common ground in this discussion. I really do. But I don't think there is any to be found and therefore I see no point in continuing it any further.
Dave
You are completely wrong, Dave. The article is in the process of correction:
It was corrected already the information concerning Chris Johnson, as it is a different person that the guru of SFI. - request to correct by Chris Johnson
On the next week two points will be corrected:
1. "HD-DVD promoted by Microsoft (WMV9 Pro supporting multi-channel audio 24bit 96 kHz WMA9 Pro)" is going to be replaced by:
"and WMA9 pro, supporting 24 bit 96kHz multi-channel Audio,
promoted by Microsoft." due to the fact, that only video part of MS technology had been approved for HD-DVD standard - this correction was requested by one of the members of hydrogenaudio forum
2. "The first SACD were developed in ProTools," will be corrected with "Some SACD were developed in ProTools" - request of Michael Bishop, Chief Recording Engineer Telarc International Corp.
We are working on correction.
I am going to make the measurements ASAP and find out the source of ultrasonics in different, then THX Music modes, though at the moment I still believe, that they are presented on the disks.
The article will be corrected or a follow-up will be posted.
I also "see no point in continuing it any further", because it looks that you don't look for any co-operation. Thank you.
Dave,
First of all we have results of measurements and my suggestions, explaining them at this point of my knowledge, based on statements of the respectable sources. For example, THX post-processing had been presented without any artificial ultrasonics. Then Pioneer stated that Hi-bit/Hi-sampling used in CD mode. I have no points (yet) to argue with those statements.
I tried to explore the ability that DF1706 was used in slow roll-off mode in my experiments (i.e THX Music mode switches that mode on) but since DF1706 is working in software mode, I can't do that without exploring of the DSP software. Or I need to make some additional measurements. I intend to do it.
You can't blame me for the wrong information, because it is not wrong at this point. You don't know if those images are presented on the disks or not, simply because some DVD players use DSPs processing for signals decryption at 48kHz and therefore you can't get reliable results. The same with SACD modes - DSD stream is processed through CXD2753, which has some kind of specific functions - here is the comparison of modes:
http://members.cox.net/alex_lat/Tests/SACD_modes.PNGCop-up excuse? I supplied my opinion/suggestion about results of measurements which I got, if you don't have enough information to confirm yours, why don't you condemn mine? I am ready to admit that I was wrong, but you are just talking - I see no confirmation of your statements.
... if you recall, i said to eric that i agree with your comments on alex's article and thought they were pretty spot on.as for your "rant", if you sit back and think about it you can't really compare an article written by an enthusiastic amateur with a technical paper that has gone through a review process and published in a journal.
the beauty of the internet is that it opens up access and visibility of information and opinions. of course, the quality and accuracy will vary, but it's up to each of us to filter the good from the bad. even though i agreed that you have uncovered some real concerns about alex's article, i learnt quite a few useful things from it and i am more knowledgeable now than if i had ignored the article. at the very least, i am now curious as to exactly what the 49txi does when THX music mode is engaged and how exactly does it convert DSD to PCM.
if you don't trust these articles, don't read these things. resist the temptation. but also resist the temptation to dismiss them all - otherwise you will be the one making the sweeping generalization.
the internet is full of ill-informed people who don't understand what they are talking about and make incorrect statements. however, it is also full of judgemental people who don't take the time to read things properly and jump in and criticize inappropriately. both sets of people are equally bad IMHO.
you yourself admit that you are not "qualified" to review alex's paper, then why did you jump in and call it hopeless? doesn't that make you equally as bad as the people you criticize? i'm not trying to criticize you, i'm simply pointing out that you have been part of and contributing to the "problem" that you are ranting about, if it is in fact a problem in the first place.
I completely agree with you here, Christine. Even in the published techical articles we have some doubtful or discussed information, take for exampe OOhashi's experiments http://jn.physiology.org/cgi/content/abstract/83/6/3548 and following by them NHK experiment: http://www.nhk.or.jp/strl/publica/labnote/lab486.html
People are still discussing this matter, no one claims that it was no reason to publish such information because it could be wrong. We all are humans, we all make mistekes, and probability of them is significantly higher in the unexplored areas.
Hi Alex:
This is the quote from Nelson Pass: "Although human hearing is generally very poor above 20,000 Hertz, ultrasonic frequency roll-offs produce phase and amplitude effects in the audible region; for example, a single pole (6dB/octave) roll-off at 30 kHz produces about 9 phase lag and 0.5 dB loss at 10 kHz. The effects may be subtle, but their audibility is undesirable in a piece of equipment whose performance is judged by its neutrality." (original). Thus, being aware of our hearing sensitivity to phase distortions, we can presume considerable decrease in the level of such distortions in the systems with a wider signal spectrum (including the quality LP playback)."
Did I misinterpret this?
d.b.
Hi Dan,
You are right, Mr. Pass was talking about the power amplifiers where we have no digital filtering. The approximation had been made for CDs, created with using of analog anti-aliasing filters, which are not perfect, as we know. Now completely different technologies are used for CDs creation. This is why I noted that "In case of correct CD playback (as it is implemented in devices from some High-End manufacturers) and incorrect playback of SACD and/or DVD-A, the former may have higher quality sound, defined in double blind tests"
Correct CD playeback means correctly mastered CD as well, though may be we need to add this phrase too.
Thanks for your reply Alex.
If you once again go back to the original article you will note a reference to the GIC low pass filter used after the DAC. The basics of this have been outlined in Burr-Brown application notes, and the scope shots taken included the GIC low pass filter. Yes, I think it's appropriate to mention that phase in the audio band does not have to an issue for CD, or any Hi-Rez format.
Thanks again:
d.b.
Dan,
Thank you for your input. You wrote a perfect article about the discussed matter, which I had missed somehow http://www.audioholics.com/techtips/specsformats/FIR-digitalaudiop2.php
I did almost the same experiment, using Marquee Tool in Adobe Audition 1.5 on the same track (I saved the file, deleted the file with pk extention to be sure that mirror process is not used), here is the result:
http://members.cox.net/alex_lat/Tests/Marquee_tool.PNG
I have no doubts that you are correct concerning this point, as we used DF1706, which were working in x8 oversampling mode for CDs and DVD-A (except of 192kHz, but we didn't use this mode), then PCM1704, I/V with OPA627 and LPF using OPA2134 - exactly as recommended by BB with just a bit different LPF (the original one in Pioneer 49TXi).
If you mean this phrase:
"High frequency and level noises create intermodulation interference in the audible region, plus phase distortions due to sharp spectrum edge at 22 kHz allow to guess the difference"
I used it because we don't know the process of such cut-off in that particular case, we can guess that it is due to DSP processing, but it could be the analog filtering of the initial signal as well or more probably combination of DF and analog filtering in PCM1738, which can shift the phase. To avoid misunderstanding I used this sentence:
"In case of correct CD playback (as it is implemented in devices from some High-End manufacturers) and incorrect playback of SACD and/or DVD-A, the former may have higher quality sound, defined in double blind tests (ABX eliminates the placebo effect, or the autosuggestion influence of the listener on the final results)"
It means that in the correct processing we have no phase shifting in CDs ... and therefore high level of quality.
Thank you.
Glad to help when I can.
d.b.
The quote isn't appropiate.You can't compare the effect of a 6dB/oct filter at 30kHz with that of a digital FIR filter.
NP also assumes a lot.
"Thus, being aware of our hearing sensitivity to phase distortions"
Our hearing isn't that sensitive to phase distortions.The proposed systems with a wider bandwidth ar not exactly free of phase distortion either. In fact they are doing a worse job altogether.
Analog tape and lp playback are not flat withing 0.5dB amplitude.
Frank
Yes, your arguments are acceptable, Frank. Nothing is ideal in this world, but if we hear the difference and can confirm it through DBT, we need to guess and discuss it, using "brainstorming" tactics around the world, in this case may be we will find the explanation.
Given that Two Against Nature is a 48k PCM recording and the DVD-A tracks are 24/48 MLP ... That extra frequency content could only be produced by some sort of non-linear processing in their playback chain because it isn't on the disc. But they fail to recognize this.
I have this disk (actually I buy only DVD-A Advanced resolution after some mistakes) Steely Dan Two against Nature and it is "Advanced resolution" DVD-A with "This disk playes 4 ways: Advanced resolution Stereo - Advanced resolution 6 channel surround sound ...", it means Giant Records give us an idea that it has 24/96 recordings. I REALLY doubt that Giant Records provides intentionally falsified statement on the disk, if the record is in 24/48 regular resolution.
Alex, I hate to bear bad news, but "Advanced Resolution" on the disc labeling doesn't imply any particular sample size or rate. It's customary on DVD-As to present PCM recordings in their native resolution. Less than half of the DVD-As I own have 24/96 multichannel tracks, the remainder are a mix of 24/48, 24/88.2, 24/44.1, and 16/88.2. There are also reports of DVD-As with only 16/44.1 but I don't have any. You can confirm for yourself that Two Against Nature is a 24/48 PCM recording. I believe it has been widely reported. Or, if you use the "Display" button on the 47Ai player, it should tell you exactly what sample size & rate are playing. My Pioneer 45A has this feature, so I assume it's available on the 47Ai as well, and it tells me Two Against Nature is 24/48. I believe that Steely Dan's Everything Must Go is 24/96 though.
If they had any question at this point about where that ultrasonic content was coming from, it should have been cleared up after they plotted the data from the Hourglass SACD. If you look at the last plot of the Hourglass multichannel data taken directly from the DV-47Ai player, you'll see exactly what you should expect from PCM data converted to DSD: signal content out to a brick wall cutoff at fs/2 followed by DSD's rising noise floor.
What is interesting, there is NO PCM to DSD conversion in 47Ai ... no such device exists. I will explain what happens with the Taylor a bit later again :) Did you mean DSD-> PCM conversion?
No, the recording was PCM and it was converted to DSD for SACD release. A lot of SACDs are sourced from PCM recordings. The brick wall cutoff is an artifact of the original PCM sample rate and will be preserved when you convert to DSD or to higher resolution PCM. The plot you included of the Hourglass sample taken directly from the 47Ai looks exactly what it's supposed to look like.
Why don't you talk here about another SACD, Diane Krall "When I look in your eyes", which gave almost the same results as Steely Dan DVD-A?
Is this the Diana Krall you used in your article? If so, look back at my post and see that I did note the same ultrasonic signature in your data.
I used THX Music mode intentionally, this is the best mode for me to listen to the multi-channel music, and I was wondering why it is that good. In this mode I had been able to check front channels and compare the results with Direct mode in the receiver. People, who read the article, will also listen to the multi-channel sources in the best mode, in this case in THX mode. The reason to use receiver was that the path for SACD signals and PCM signals, except of DSD-> PCM conversion in SM5816A, is the same - this allows to make the comparison better. The goal was to compare DVD-A and SACD in the best possible listening modes.
THX may indeed sound better; I have no idea since I don't have the 49TXi. But, my problem is that I suspect its use led you to some wrong conclusions. The problem may not be the THX mode, but something in the 49TXi is producing ultrasonics that shouldn't be there.
Take a look here, I had made the spectral comparison, all samples are from 47Ai, no THX processing in this case:
http://members.cox.net/alex_lat/Tests/Taylor-2.PNG
It means your theory concerning non-linearity in the DSP processing of receiver is not correct.
If indeed there is no THX processing in this case, all that means is that the problem is somewhere else in the 49TXi. In the above linked picture, the output taken from the 47Ai looks good but the extra spectral content appears again in the output from the 49TXi just like in the plots published in your article. The change can't be taking place in the 47Ai, because iLink transmits a DSD stream and the 49TXi performs the PCM conversion. So it must be happening in the 49TXi, and by definition the process has to be non-linear otherwise the extra frequency components could not be produced.
It would be valuable to track down exactly where the extra ultrasonics start appearing in the processing chain. However, I'm not sure how easy that will be to do if all you can do is turn on and off certain settings in the menus. If you aren't able to track it down, then in my opinion you are best off taking data only from the 47Ai.
As if the cutoff at 22 KHz is due to some sort of filtering during playback.
You hit the nail on the head! It looks as I'd found the reason of such sharp cut-off in the process of playback comparing the different modes of DSD decoder CXD2753 ...
http://members.cox.net/alex_lat/Tests/RFSACD.PNG
http://www.avsforum.com/avs-vb/showthread.php?postid=4216351#post4216351
I'm not 100% sure about this, but I believe the modes under discussion here amount to higher order vs. lower order noise shaping. Using higher order noise shaping will increase S/N in the audio band but with a much faster rise in noise as you go up in frequency. Lower order noise shaping gives you a flatter noise floor but S/N won't be as low in the audio band. If so, it will only affect the noise floor, it doesn't filter the content, and honestly I'm not sure any SACDs use lower order noise shaping. As I mentioned before, the brick wall filter characteristic you see in the Hourglass samples are a product of its PCM heritage.
The difference IMO is in the ultrasonic images, but not separated from the audible contest, here is the scientific research, confirming it (the full article in in pdf file in the right upper corner of link)
http://jn.physiology.org/cgi/content/abstract/83/6/3548
I think you're jumping to conclusions. Your data shows a clear change taking place in the 49TXi that is altering the samples and adding ultrasonic content that is not present on the disc. You have also admitted that using THX mode changes (improves) the sound. Until you can track down what's causing the change and can determine exactly what the THX mode does to the sound, I don't think you can conclude anything about playback of raw SACD vs. playback after PCM conversion.
Dave
. . . . but it has been suggested that this MAY have been upsampled from 24/48, but as yet I've not heard it officially.My Denon DVD-A11's display tells me that it's playing at 24/96kHz MLP (NOT 48kHz).
By the way, "Everything Must GO" is 24/96kHz MLP for the 5.1 track, and 24/192kHz MLP for the 2-ch.
I just played it myself and got the same result.Sorry Alex, I should have waited until getting home from work to reply. Anyway, I don't think it changes anything. I'm still pretty sure it's a 24/48 recording. If there is any doubt that the processing in the 49TXi is responsible for the extra ultrasonics, simply re-measure Two Against Nature taking the output straight from the 47Ai. You should get something more like this:
http://www.stereophile.com/features/282/index5.html
Dave
. . . it is well known that Panasonic and Pioneer DVD-A/V machines can do this sort of thing in realtime with a "remaster" function.
Using the JT Hourglass SACD, Alex made comparisons between multichannel data taken from the 47Ai player and the same data taken from the 49TXi receiver. The extra content only shows up in the data taken from the receiver, meaning it's not on the disk. See the links in my reply to Christine.He didn't provide the same comparison for Two Against Nature, but the multichannel data taken from the 49TXi also shows extra stuff that has the same characteristics as the extra stuff in the Hourglass data. And in Stereophile's similar analysis of Two Against Nature, it doesn't appear.
The data for DSOTM and Diana Krall also exhibit seemingly extra ultrasonics of a similar shape and level, only on those discs there is no sharp cutoff to make it obvious.
I see no other reasonable conclusion from all this other than it being an artifact of the processing in the 49TXi.
Dave
Dave, we will check it out. Only one possible reason in 49TXi to add such ultrasonics is switching to slow roll-of in digital filters DF1706. They work in software mode, therefore the modes are settled by DSP, I can't track such switching on the schematics. I didn't pay attention, was hi-bit/hi-sampling on or off in my measurements, as it was advertised for CDs, DVD-V (DD and DTS) - low resolution sources only. No one word about any improvement of sound for SACD or DVD-A ...
Here is the explanation of Audio Scaler, provided at Pioneer (Europe) website:
http://members.cox.net/alex_lat/images/Audio_scaler.PNG
But you had pointed to an interesting question. We didn't have the explanation for the line at 22kHz or 24 kHz, which is presented on almost all spectrums. We also know, that in advertised AX10Ai(59TXi) signals are processed in DSPs at 96kHz, that means - for the previous model 49TXi it could be 48kHz in all DSPs or partially in some of them (we have 2 SHARCs and Motorola DSP in it).
We need some additional measurements, and if they will confirm Dr. Gresinger's, yours and John's suggestions and measurements concerning 24/96 Steely Dan DVD-A and James Taylor SACD, that will be an idea for another article - Smoke and Mirrors in AV industry ...
for the mastering facility.Everything must go was was recorded to tape for 'sound enhancement' in an intermediate mastering step. This was converted to digital for the final mastering.
Frank
The recording of EMG (including the analog stages) es described in detail here:http://www.soundonsound.com/sos/aug03/articles/steelydan.htm
Couldn't remember the link myself.Frank
Dave,Are you sure you can conclude that the issue is in the 49TXi? IMO, based on what we know, it's simply not coming from the discs.
Whether this is from the 49TXi, the cabling or the PC or the soundcard is not yet defined as best as I can tell.
Regards,
John Kotches
Jonh,
It can't be a soundcard, as we have different results in different situation plus I made the measurements with the loop for the soundcard. It can be 49TXi,I have to check some suggestions. How do you know that it is not coming from the disks?
In the case of Two Against Nature and Hourglass, they are based on 48K PCM recordings.Anything beyond about 22K isn't coming from the original recording.
Regards,
John Kotches
John,
Are you 100% sure that no one used something as Aural Activator to extend the bandwidth in the process of re-mastering of Steely Dan "Two against nature" to Advanced resolution format? What was the reason to put the label "Advanced resolution" on DVD-A if the recording is still in 24/48 (The Giant Records had fooled us)?
I am going to make the measurements in other then THX Music modes (to keep multi-channel tracks as the sources) and will post the results ASAP. I can see only one technical ability to create the additional artificial ultrasonics in 49TXi at this point - switch sharp roll-off mode in DF1706 to slow roll-off, as it had been done in Legato pro. In this case Pioneer will not look good ...
"Advanced Resolution" simply means the audio is higher quality than CD. 48k/24-bit is considered to be Advanced Resolution. (It's just a marketing term)
http://www.soundblaster.com/dvd-audio/
"ushering you into the Advanced Resolution™ era of 24-bit music fidelity with 192kHz in stereo and 96kHz in 5.1"http://www.stereophile.com/news/10861/
"Advanced Resolution DVD-Audio is the ultimate listening experience," states the WMG announcement. "With a sampling rate and bit depth that at least double the resolution for the current CD standard, DVD-Audio discs deliver sound quality that is significantly closer to the master recording than is possible with CDs."http://www.musik-idealo.de/4R1P246148C5K3-Cracked-Rear-View-DVD-AUDIO.html
"Hannah Jane (Advanced Resolution 96/24 Surround Sound Mix)
Hold My Hand (Advanced Resolution 96/24 Surround Sound Mix)"http://www.dvdreview.com.au/cgi-bin/specific_movie.cgi?id=18835-64.68.82.33-1091527230&apn=0093624781493
"the music on this disc can be played as DVD-Audio Advanced Resolution Surround (ie, 6-channels @ up-to 96kHz / 24 bit) or as Advanced Resolution Stereo (ie, 2-channels @ up-to 192kHz / 24 bit).
"Concerning this particular VD-A:
http://www.warnervision.com.au/bio.asp?id=1883
" STEELY DAN Two Against Nature Disc Content Audio:
* Advanced Resolution Multi-Channel Surround Sound (96 khz/24-bit) DVD-Audio Players
* Advanced Resolution Stereo (96 khz/24-bit) DVD-Audio "
Alex,Do a little research on S'phile's website. Atkinson shows it (Two Against Nature) is a native 48K recording.
BTW, Fagen's Kamakariad is also an original 48K recording that was converted to analog, then A/D'd @ 96K for delivery. They list it (quite honestly IMO) as a 48K.
I'm not concerned at all with marketing fluff. Advanced resolution simply means > CD fs, > CD sampling depth. Nothing more, nothing less.
Regards,
John Kotches
John, If you mean this article:
http://www.stereophile.com/features/282/index5.html
And Steely Dan "Fig.3 Spectrogram of Steely Dan's "Janie Runaway," from the Warner DVD-Audio sampler. Original DVD-A data recorded at 24-bit/96kHz" it is a bit different story, IMO.
But anyway I am going to make the measurements ASAP and then we will know.
http://www.warnervision.com.au/bio.asp?id=1883
http://www.scotthullmastering.com/Articles.html
"But for this project, the entire signal path was digital – but utilizing the higher sample rates and bit widths. The Genex source went directly to my Sonic Solutions editing system recording at the full bandwidth of 96x24. After the mixes were edited and compiled, the 96x24 bit AES signal was routed to my Z-Sys 96k 24-bit 6 channel digital EQ. We only needed 2 channels for this version, but this is such a nice sounding digital EQ."
Clearly, the graph in figure 4 shows that the original recording is 48K, notice the absence of content above 24K in the FFT derived spectrum.Why you can't accept that, and go forward?
Regards,
John Kotches
The problem is that it looks as we have different signals for stereo tracks and multi-channel tracks - take a look at the background noise floor on Fig 4 ...
John,In the original article, Alex provided one plot of data taken straight from the 47Ai by the same PC, soundcard, etc. and it looked normal. Also, one or two of the PNG files linked in his follow-up message also contained data taken straight from the 47Ai and that looked normal too. Given that the 47Ai transmits the DSD bitstream over iLink, I think that narrows the problem down to something inside the 49TXi.
Dave
Thanks for your detailed answer to the points raised, hopefully some consensus will be found.I have one reflection about this discussion: Maybe there is a need for some common sets of methodological standards in the future, which would make comparisons easier, e.g.
- Recording should be done using the analog outputs, unless there is a specific reason for using the digital output, and the key data for digital vs analog should be provided as an indication of any potential bias or distortion
- Recording should be done directly from the player to the capture device whenever possible, and if extra amplification is required to amplify the signal and obtain the highest possible resolution, that decision should be stated in the analysis
- All data should be analysed without normalization if possible, unless a direct comparison requires it.
etc?
Then, as more data is collected and published on the various forums (fora?), it would be possible to re-use what others have already measured, and benchmark the results with different players, etc.
Just my little 02
Best,
Eric
"no THX processing in this case" - I have to correct myself should read between two first pictures.
Actually I invite you to contunue the discussion in a modern forum, as AVS, for example, it is not easy for me to have no editing option here.
"It means your theory concerning non-linearity in the DSP processing of receiver is not correct." - the above mentioned picture doesn't confirm this my statement. Sorry for any inconvenience. I have made an other picture - the difference between stereo track and multi-channel track for Taylor ...
http://members.cox.net/alex_lat/Tests/JT_49TXi.PNG
does anyone still think that THX Music processing can add such HIGH level ultra-sonic images to the original signal? I really doubt it ... but who knows ... In this case the whole THX post processing (THX Music at least) is some kind of fraud, though ...
Sorry, but you don't seem to have any idea what you're doing.
ZS is going to come back here for a stretch and you're going back there.We've had enough for the month.
Don't bother replying to this post.
Thanks, Chris
really? May I ask you to explain step by step where I am wrong, from your point of view?
Why bother? You don't even know the specs of the recordings you were examining.
How can I prove something for you if you have no arguments, only condemns? Please provide the specifications and sources of those specifications, and we will discuss them.
Why don't you just admit you're wrong?
Well, as you wish - I just admit that I was wrong talking to you, OK?
He's our local trollCheers
Eric
Thanks, Eric.
Wow, this forum is awesome, no text formatting, no editing/corrections of mistypings, no pictures ... :(
Sorry for typing errors, I used to correct them after the posing in other forums ...
I actually like the layout of this forum. But it any case, you can use the preview feature to check for mistakes. Also, you can do text formatting,
such
asthisand embed pictures too. You just need to use standard HTML tags instead of PHP tags. There are a few bugs though, but for the most part it works. If you're a registered user, you can also change the default forum/thread views to something you're more used to.
Dave
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