Computer Music Audio Quality
bramankp -- Tue, 12/27/2011 - 08:51
Published in TAS #219, I'm having some real problems with this article co-authored by Charles Zellig and Jay Clawson.
While most of the article is actually quite good I have a very hard time with the following sentence, "Although JRMC reported an accurate rip for all reading speeds, and are bit-for-bit identicle at all reading speeds, we are still able to detect sonic differences in the resulting files."
Really? Maybe that's not exactly what the authors meant to say but it's the equivalent of saying one can make a copy of a ripped file and somehow the exact copy sounds different. I want to trust what's being presented in the article but this is a sticking point for me. The same bits (*the same bits*) played back from a different position on the hard drive sounds different?
Someone please clear the air on this.
All content, design, and layout are Copyright © 1999 - 2011 NextScreen. All Rights Reserved.
Reproduction in whole or part in any form or medium without specific written permission is prohibited.
Reproduction in whole or part in any form or medium without specific written permission is prohibited.
Yes, you're right, I didn't mean to imply that upsampling would create identical files, just that the result would not necessarily be closer to the "original," but I guess that's not really the point anyway. If it sounds better to the listener, it sounds better, but again my point is that I'd prefer to see a blind test to determine whether there is a noticeable improvement (or degradation) in quality for the listener, as opposed to a perceived change due to expectations.
Interesting how polarized this thread is.
I just got my new iMac hooked up to my system. I run a Bryston DAC, and all my files are Apple Lossless. I run Airport Express to my DAC using Toslink (the only way to get a digital feed). Here are my observations:
My CD transport is a good one, and uses a Nordost Silver Shadow cable. It has every advantage to sound better. Both the CDP and iMac output only 44.1/16 sound files. The DAC has the upsample feature ON.
The sound, from identical discs on the CD or iMac shows the iMac source to sound better. Treble is better, more defined, and suprisingly, the soundstage is better. I am hearing things from the iMac that I didn't hear from the CD (such as subtle reverb, nuances in the high end). And I haven't gotten into high res yet. Scary thought.
I am not using anything other than iTunes. I kept it simple.
I would like to get away from the Airport Express but the sound has (yet) not dropped out or skipped or stalled. The part I agree with is this: digital sounds better from a hard drive. As to different file players; I don't know.
If it were a case of expecting better: I would expect the expensive CD transport and cable to sound better. But not so. And the treble sweetness is as distinct as my switching from a pure solid state amp to a pure Class A solid state amp (the sound difference was immediately obvious). And other than the cost of the iMac, the Airport/router was about $300 and the Toslink cable $70. The difference is even more striking when comparing cost. And the user interface on the computer is a hands-down winner. Yes, I like the equipment in my audio rack, but unless the computer is occupied, it is clear my CD transport is obsolete, but still useful. I had a suspicion when I bought the DAC that I was right: it is the new "central" item in the new digital system. WIthout a good DAC you are going nowhere.
The future looks good for my digital front end. Hopefully Apple will allow high res to be played wireless over Airport Express soon. Very soon.
Great rig, Blackfly. Keeping it simple has advantages...:) And wait till you hear high rez...
Steven Stone
Contributor to The Absolute Sound, EnjoytheMusic.com, Vintage Guitar Magazine, and other fine publications
Sadly I cannot find a way right now. I cannot use Airport Express (does not support it) and running a cable 30 feet from the computer to DAC is not feasable; where do you find a 30' Toslink cable? But the bare 44.1/16 sound right now is very good, even better when the recording is superb (think Diana Krall, Melody Gardot, The Police etc....)
I found the remark
"Although JRMC reported an accurate rip for all reading speeds, and are bit-for-bit identicle at all reading speeds, we are still able to detect sonic differences in the resulting files."
by Charles Zellig and Jay Clawson to be quite illuminating. If you go back to their tables of results, you can see, if I remember correctly, up to a 40 point spread in the sound quality they report of files with the same digital sound content. That's remarkable. If you assume that they really did think they were hearing these differences, then this makes a striking statement about the accuracy of subjective reporting: It shouldn't it be taken with just a grain of salt, it should be taken with a 50-pound block.
Of course, it not at all clear what these reports of sonic quality of 100 or 80 or whatever really mean. What does it mean to say that one file sounds "20 points" or "20%" better than another? It's kind of laughable, really.
Frankly, after reading Zellig's bafflegab about quantum effects and jitter above, I'm not sure these authors either are or are capable of being intellectually honest; in any case, their articles themselves give me the impression that when it comes to digital electronics, they don't really know what they're talking about. That suggests there's a crying need for competent reviewers of digital audio equipment.
And that brings me to TAS itself. Are Zellig and Clawson representative of others who review for TAS? TAS has steered me to some really great equipment over the years, not to mention great music and recordings, but because of these articles by Zellig and Clawson, I now find myself much more skeptical about what I'm reading in TAS, especially when the distinctions being reported are supposed to be subtle ones.
I'm glad that TAS is getting serious about computer audio, but I hope TAS can get past this fiasco and develop some serious journalistic expertise in this area of audio reporting.
I do not know how accurate the conclusions in the articles are; in my own contexts with decent equipment, the differences are frequently not subtle.
Before anyone criticises the articles, they should perform the same experiments for the same amount of time or STFU. One does not have to have "Golden Ears" to distinguish across platforms (Vinyl, SACD. Redbook, MP3) so I see no reason why ones subjective observations hould be so criticall denigrated.
While subjective, the protocol was rigorous and to contest the results demands similar diligence in experimental design.
TLE
Tleddy - your claim makes perfect sense if listening to entirely different formats like WAV vs. mp3. They are different files containing different information. The conclusion that everyone has a problem with here is that two identical files, containing identical information, can lead to such consistently different results. Certainly someone might subjectively hear a difference when listening, especially if the listening experiment is not done blind. Anyone who knows a little about computers can only conclude (1) that the files are not truly identical (in which case something is wrong with the tools used to convert them to FLAC and back to WAV) or (2) that the study was not truly blind (in which case the expectation that one was going to hear worse results from a file that had been converted could bias the study). (1) is highly unlikely as if there was such a problem with those tools, you'd be experiencing other problems as well and the files might be unreadable. In any case, (1) is easily checked with other tools. For (2), you are right, someone with more expertise in computer technology generally (not just audio) needs to replicate these results.
Mr. johnsimms:
It appears that you have missed the whole point of our quantification of sonic differences, the methodology for which we took great pains to explain in Part 1 of our article. So, first let me first reiterate our measurement method.
Our purpose in undertaking this study was to document our experiences in the field of computer audio and to alert audiophiles with typical PC’s to the many variables associated with computer playback that affect sound quality. Secondarily, we wished to bring some quantitative discipline to the typical subjective review process that could be easily replicated by any audiophile using their own systems and hearing acuity. Why did we do that? We wanted to provide a way for readers to understand and be able to evaluate the significance of our experiences within the context of their own systems and their own hearing acuity. Instead of taking our word, we intended for readers to perform their own sonic tests, the results of which would no doubt differ from ours for many reasons.
To this end, we created a sonic yardstick defined primarily by the listener’s estimate of the subjective difference in sound quality between a Reference Recording CD at 44.1 kHz/16-bit and the same recording on DVD in its original resolution of 176.4 kHz/24-bit. In no way do we assume that 20 points on our scale would have the same significance to you or another listener as it has for us. It could be smaller or it could be larger depending on the resolution of the system. In terms of allocating one’s audio efforts and expenditures, the utility of our quantitative scale is up to you, not us.
Now that I have touched upon your 20 point reference, I would like to point out that nowhere did we refer to a 20% difference…. Also, I regret that you did not understand the intended wry humor in my reference to quantum physics.
Once you have repeated our experiments with our methodology it would be possible to have a legitimate discussion with you, but absent that I cannot give your comments serious consideration.
Chuck Zeilig, The HiFi Doctor
The fundamental problem with repeating your experiments with your methodology is that your methodology is flawed. It produces insufficient objective data to support your conclusion. Subjective qualitative analysis is not a substitute for objective quantitative analysis.
Record the MD5 checksum of the imported WAV file. Convert that file to FLAC. Convert the FLAC file back to WAV. Compare the checksum of the new WAV file with the original WAV file. If they match, then the FLAC codec and the conversion process can be definitively ruled out as possible sources of any sonic differences detected during listening, and your conclusion can justifiably be rejected. Failure to do so would be an egregious affront to the scientific method.
Incidentally, I did the experiment I described above and found that the checksums matched exactly. Your conclusion is invalid.
Proben and thesurfingallen:
Gentlemen,
Please read our methodology again and do your own testing. You are proffering opinions, not facts. We are not talking about feel good differences or expectation bias. We are talking about what sounds more like the master tape (or the corresponding high resolution file). Proponents of double blind testing are absolutely correct in certain areas of subjective and medical response research. However, with respect to auditory perception, a thorough understanding of the implications of modern research into how the ear-brain system works suggests that double blind testing is flawed and not sensitive enough to pick up the kind of differences that most intellectually honest reviewers and audiophiles hear and hear fairly easily. Do your own testing and with an open mind. Then report your findings.
Chuck Zeilig, The HiFi Doctor
Still clueless I see. Fortunately for the ongoing credibility of TAS magazine it appears that not all its reviewers are so out of touch.
Proben and thesurfingallen:
Let me add to my previous post. Lest you think that I don't understand the basic problem you have with our results, let me cite one simple example. Take the results of Table 5 in Part 2 or our article. Here we report that differences in ripping speeds produce audibly different WAV files that measure identical in EAC. Impossible you say. I say, do the experiment yourself. I believe our methods are reliable and I believe our results. I cannot explain them. There must be a rational explanation. Perhaps if you can replicate our findings and with your presumed superior understanding of the inner workings of computers (and/or DACS), you will be motivated to probe further for an answer. Have at it!
Chuck Zeilig, The HiFi Doctor
Mr. Zeilig,
With all due respect, I assume that you agree with me that audible differences between bit-for-bit identical files, caused by the content of the file itself, is not the most likely cause. I understand you are not able to explain them, but did you do any effort to do so? Personally I would have contacted the manufacturer(s) of the used hard-drive(s) asking if there was any explanation for such irregular behavior.
As for my motivation to probe further for an answer... No need; I already have one.
Kind regards,
Peter
To the surfingalien:
I didn't mean to get drawn back into an extended discussion again but I did want to respond to you. I had actually done the same ripping test many years ago on a wholly different computer and equipment. I got similar results then and I believe others have also reproduced these results before we did the current tests. So, I don't think these findings are unusual or without precedent. When we began this investigation, we did not intend to make any new discoveries but only wanted to describe for audio junkies like ourselves the variables involved in bending computers to audio usage. Since publishing our work, we have heard from many people (in some cases highly authoritative) who have observed files which measure the same sounding different. So as has been said before, extraordinary results require extraordinary proof. We continue to improve our methodology to bring more convincing evidence to the validity of the observations and do what we are able to track down causes, or at least, likely clues to the causes. Meanwhile, the reality of the situation still remains. If you want to maximize listening quality (whatever the underlying causes or computer artifacts that may be involved), and have a curious mind, "do the experiment" for yourself and see what you get. To say that you already know the answer is not doing the experiment.
Anyway, thanks for your carefully worded and reasonable comments.
Chuck Zeilig, The HiFi Doctor
It would be interesting to see the name and qualifications of even ONE "authority" who supports this view. And exactly what does "measure the same" mean with regard to computer files? Either they are identical, or they are not; what exactly are you "measuring"?
I'm sure you've noticed that there have been many apparently valid criticisms of your experimental methods (posted here and elsewhere) none of which have been addressed by you. Without acceptable methodology, any results from a "scientific" study are invalid, or at best suspect; surely you know this?
I do not like to harp... however, my reply to all of the critics of the article remain the same. I think that Chuck has been a true gentleman in the face of several ad hominem attacks. So, I say again:
"Before anyone criticises the articles, they should perform the same experiments for the same amount of time or STFU."
Manetti
What makes you think we and others haven't done exactly that? Furthermore, I don't think there have been any ad hominem attacks, just good (although persistent) questions about published methods and results, none of which have been constructively answered. Just saying "we stand by our results" is no answer to reasonable questions about methodology or reproducibility of results.
Mr. Zeilig,
I would like to do a test myself with regards to quality-loss caused by the WAV to FLAC to WAV conversion.
Can you tell me after how many cycles of compression & decompression you believe the final WAV-file to become so degraded that even people with a limited audio-setup and mediocre listening experience (or capabilities) can immediately hear a difference? This can be any number as I will script the procedure. Maybe 100 times, 500 times or 1000 times?... Not a problem for me.
For the test I will use my regular Windows7 PC, Foobar2000, EMU-1820 sound device, and a Sennheiser HD600 (connected directly to the E-MU).
Also, did you use default settings for the FLAC-compression settings?
Thanks,
Peter
Mr. Zeilig,
As I was curious I picked a number of conversion cycles myself: 250
I used Kari Bremnes song "Sangen Som Søng I Oss Alle" from her album "Svarta bjørn" which I extracted from CD twice using EAC with the following results:
Track 8
Filename C:\Users\Peter\Test\08 - Sangen som sng i oss alle.wav
Peak level 98.2 %
Extraction speed 13.5 X
Track quality 100.0 %
Copy CRC E884848A
Accurately ripped (confidence 13) [B049CC33] (AR v2)
Copy OK
I renamed the first rip to T0.WAV
I created a simple script to repeat the WAV to FLAC and the FLAC to WAV conversion 250 times, beginning with the T0.WAV and taking the resulting T#.WAV on the next pass. The script is as follows:
For I = 0 to 249
strFNWAVIn = "T" + Cstr (I) + ".WAV"
strFNWAVOut = "T" + Cstr (I + 1) + ".WAV"
If I = 0 then
strDIP = ""
Else
strDIP = "--delete-input-file "
End If
objShell.Run "C:\Users\Peter\Test\Flac.exe "+ strDIP + "C:\Users\Peter\Test\" + strFNWAVIn + " -o C:\Users\Peter\Test\TEST.FLAC", 1, true
objShell.Run "C:\Users\Peter\Test\Flac.exe -d --delete-input-file C:\Users\Peter\Test\TEST.FLAC -o C:\Users\Peter\Test\" + strFNWAVOut, 1, true
Next
As I was only interested in the final file (T250.WAV), the script deletes all other T#.WAV's except the T0.WAV.
I used a tool called WinMerge to verify T0.WAV and T250.WAV to be absolute bit-for-bit equal, which was the case.
Then I used Foobar2000 with the ABX plugin to allow fast & easy switching between T0 and T250.
You obviously have to take my word on this, but after over an hour listening I was not able to tell any difference whatsoever between both files. To take it too extremes, I modified the script to do the cycle 1000 times, which is running right now. I will edit this post and report my finding on T0 and T1000.
Regards,
Peter
At least one other person (besides me) ran that same test, comparing file 0 to file 1000. As with your experience, we have been unable to discern a difference on our equipment, and as you noted the audio files appear identical by MD5 as well as null testing in an audio editing program (Izotope RX Pro).
Mr. Zeilig,
I have also completed the 1000-cycles conversion and did another listening test. This time I only tried for half an hour to distinguish any difference, but just like the 250-cycle version I am unable to hear any difference whatsoever.
In my opinion, if your findings regarding increased degradation with each conversion-cycle are indeed correct, this up-scaled experiment should have resulted in a file with massive and very easily discernible audible degradation. I can not confirm this to be the case.
I hope you can appreciate my efforts in this matter, and I am looking forward to reading your thoughts about it.
Kind regards,
Peter
Edit:
As it is rather obvious that I have a rather strong bias in this matter, I can understand people who scratch themselves behind the ear and think "Yeah right! He is a confessed "naysayer" coming up with "evidence" to prove his point". Fortunately, knowing that bias exists allows me to set it aside and do some unbiased testing. Furthermore, I have nothing to win (nor to lose) here.
Peter
I read the articles in TAS #219 and TAS #220 along with this thread and I have some questions whether to re-rip my cds into wav files. I used db power amp to rip my files to flac and from what I read in TAS #220 it supposed to sound better in wav. Has any one else confirmed this?
I also have a question concerning the hardware I'm currently using. Instead of using my computer as the source, I'm using the SB Touch with a Western Digital WD Elements 500 GB USB 2.0 Desktop External Hard Drive. I had the SB connect to the W4S dac1 and was not impressed with the sound. I compared this set-up to the Oppo 95 playing the cd version and the Oppo sounded much more detailed and smoother. Is the weak link the SB touch, the external hard drive or the dac.
Little hard to tell... As far as I know the W4S DAC is excellent, so I doubt it will sound worse than the Oppo. How do you connect the SB to the W4S?
As for FLAC vs. WAV. Why don't you convert a FLAC into a WAV (or re-rip) and listen for yourself?
Peter
Peter,
I used a Black Cat coax cable between the SB and the W4S. Concerning the W4S vs the Oppo, I compared both thru my Sim I-7 and Focal 1027be speakers. My brother and I compared various type of music including jazz, both male and female singers. We both concluded the sound was bit smoother and a bit more detailed playing the original cd thru the Oppo than playing the flac file thru the W4S. We also compared the W4S vs the SB internal dac and the SB was harsher and and less detailed.
So here's my question again, could using the SB with an external drive affect the sound quality or was it the W4S dac?
Yes, it could be that a SB with external HD can affect sound. It also can be the DAC.
You can ask the same question everywhere, but you will get biased answers this way. Someone that does not like the W4S will tell you its crap, and the same thing goes for the SB
Really, the thing is that you need to experiment for yourself:
- listen to WAV instead of FLAC. Hear an improvement? Yes? Maybe the SB's firmware is not up to date, No? Move on!
- Store a few WAV and FLAC files on a USB memory stick and listen again. Sounds better? Maybe try another HD
Etc. etc.
Peter
Peter,
I guess you're right concerning the bias answers to any piece of equipment. As you suggested, I'll experiment with both wav and flac files to hear what sounds best on my system. I do have different HD for back-up and compare it to the current HD. Thanks, Ron
I read the articles in TAS #219 and TAS #220 along with this thread and I have some questions whether to re-rip my cds into wav files. I used db power amp to rip my files to flac and from what I read in TAS #220 it supposed to sound better in wav. Has any one else confirmed this?
I also have a question concerning the hardware I'm currently using. Instead of using my computer as the source, I'm using the SB Touch with a Western Digital WD Elements 500 GB USB 2.0 Desktop External Hard Drive. I had the SB connect to the W4S dac1 and was not impressed with the sound. I compared this set-up to the Oppo 95 playing the cd version and the Oppo sounded much more detailed and smoother. Is the weak link the SB touch, the external hard drive or the dac.
Tried a scientific experiment: FLAC vs WAV vs MP3 vs M4A. The results are here:
http://www.computeraudiophile.com/blogs/FLAC-vs-WAV-vs-MP3-vs-M4A-Experiment
Mitchco-
At last, a fine scientific analysis and commentary. An EXCELLENT JOB!!
Manetti
A very informative entry without any polemic, and a fine piece of work, inlcuding all the pictures. What strikes me most is the truly measured comment on audible differences in file formats: "For those that are hearing a difference between lossless file formats of any kind, it is not the file format..It is not that the files are different, it is how your system is interpreting those files that is different. The problem is diagnosing where the differences are" This comment is to the point and worthwile following.
It's not scientific to compare an M4A file to a FLAC file that is clearly from a different master. That particular null test offers no meaningful information. We cannot tell which differences result from the differing maters and which ones result from the lossy compression.
The FLAC vs WAV aspect was interesting, and confirms what many here already know, that there is no difference between lossless formats, audible or otherwise.
AS to the ad hominem... stating that one is "delusional" seems to me to meet the criterium.
Your inquiry concerning how I know that no one has done the same expriment, well, I misspoke. I should have said that no one in this thread has stated that they have attempted to duplicate the experiment, and if they have they have not posted the detailed results of such experiment.
My apologies for not being more accurate in my statement.
Quote from Chuck Zeilig above: "Proponents of double blind testing are absolutely correct in certain areas of subjective and medical response research. However, with respect to auditory perception, a thorough understanding of the implications of modern research into how the ear-brain system works suggests that double blind testing is flawed and not sensitive enough to pick up the kind of differences that most intellectually honest reviewers and audiophiles hear and hear fairly easily."
This is what I have a problem with. If the differences are heard "fairly easily," they should be noticeable whether the reviewer is blind or not, right? The worry is not about the intellectual honesty of the reviewer so much as their unconscious expectations. Blind testing eliminates the possibility of such expectations playing a role in one direction or another. The claim that blind testing is "not sensitive enough" to pick up differences that people "hear fairly easily" makes very little sense to me.
This does help me better understand what happened here. Until reading this comment from Chuck I made the assumption that all the testing in their articles were done blind. I think it would be helpful to readers of TAS to inform them clearly that these articles were not based on blind testing at all (or, if some of the claims were blind-tested, to identify which ones -- part 4 of the article, which I just finished reading, does at one point refer to blind comparisons of upsampling). The real problem is the claim that bit-for-bit identical copies of the same WAV file sound different if the WAV file is compressed to FLAC and uncompressed to WAV several times. We now have several experiments from readers suggesting that not only is that claim implausible, it is in fact impossible, as both the WAV and the FLAC files convey the exact same analog information. If the progressive degradation claim were true, there should be a certain point at which the degradation of the sound quality is so noticeable that the file is unlistenable -- like the cumulative effect of converting from WAV to mp3 and back to WAV (which will be quickly noticeable and after 5-10 conversions will produce an unlistenable file). Certainly after 1000 such conversions you'd think someone could tell the difference between files on an ABX test to say the least.
Proben,
To be clear, all testing was performed with a single blind, randomized protocol as stated in Part 1. So, please don't misrepresent our methods. The arguments for or against the sensitivity of double blind testing in picking up subtle (or not so subtle) auditory differences is not winable in this forum so lets agree to give this one up. The explanation for why we were able to hear differences in seemingly identical wav files remains unanswered and we continue to investigate these results in a variety of ways. We will let you know what we find. Possible explanations that have been proffered so far by industry veterans, other than a placebo effect, are degree of fragmentation and position of the files on the hard drive, differences in file offsets,and differences in the order in which files are loaded into the memory player used for playback.
Chuck Zeilig, The HiFi Doctor
I was not misrepresenting your methods, I was responding to your specific comments which made it seem as if the testing was not blind (and in fact you argued that blind testing was inadequate in that comment). I'm glad to hear that all testing was done blind (I will have to re-read part 1, but is it fair to say that these tests included ABX with the various files, not just a "which one's better" question?)
The various possible explanations make some sense, but from the claims in the essays, I'm assuming you found consistent degradation of a WAV file every time it was compressed to FLAC and back in blind experiments. If that is the case, it would be a remarkable coincidence that each WAV file was copied to a progressively more fragmented position on the hard drive with each compression and recompression, for example. I assume you could easily verify whether this is the case by redoing the experiments with an empty hard drive. The other explanations might be less trivial to verify but not a whole lot as these are software issues dealing with playback rather than differences in the actual files themselves. If you could better control the conditions of playback (as at least three participants in the discussion seem to have been able to do), you ought to be able to test whether there are differences attributable to the files themselves.
Amazing. It's taken you until now to admit that in fact the files themselves probably DON'T sound different, something you should have been able to determine BEFORE the articles were submitted for publication and certainly before they were published. Hardware or software specific findings, in fact the very same explanation that was originally proposed by me and anyone else who bothered to think about it.
Chuck,
"The explanation for why we were able to hear differences in seemingly identical wav files remains unanswered and we continue to investigate these results in a variety of ways."
Here's your answer:
A common-sense explanation of audiophile beliefs
http://www.ethanwiner.com/believe.html
As for jitter or other playback issues, this is trivial to overcome. When I do audibility tests I load the files into a program such as Sound Forge and play them from there. If a drive is so badly fragmented that it can't be read in real time, Sound Forge will stop playback and tell you. Same for SONAR, another program is use to do listening tests and also null tests. Indeed, if you load two files you believe sound different into a DAW and they null, that proves the files are identical and it's only human perception that changed.
--Ethan Winer
blow_666 wrote: "As for jitter or other playback issues, this is trivial to overcome."
I would be careful about lumping jitter into your "other playback issues" bucket. What you're talking about, by loading an audio file into Sound Forge, detects throughput issues that are fairly obvious to detect anyway. Jitter involves specific timing of feeding bits into the DAC and has nothing to do with how the bits are arranged in permanent storage.
Someone earlier mentioned jitter could be made worse if the file is fragmented, so that's what I addressed. But normal jitter, the type everyone talks about, is not an audible problem anyway. Yes it can be measured, no you can never hear it. It's a marketing strategy to get you to toss all your old digital gear and buy new "low jitter" stuff. I address this in my AES Audio Myths video, which references example files on my web site that prove the point.
--Ethan
I like Ethan's work. I have to think that all who listen critically will notice that when we sit down to listen, we find that our Significant Other has moved our listening chair a bit, perhaps to vacuum... and, darn it, the system sounds different. We then figure out that the chair has been moved only slightly, but we have to reposition to get the "perfect" sweet spot.
For casual listening (there is such a thing) we can compromise on the sweet spot, but not for serious listening. The slightest deviation from our sweet spot is noticeable and annoying.
I also wonder if the sweet spot also has dependency on other objects in the environment... say a table, chair, lamp etc. is moved a bit. What then the effect?
I should note for the record that my hearing is not what is used to be... I am 70 now and my measured hearing acuity has an upper limit of
10kHz. Partly a result of aging, but I had a head start in Basic Infantry Training, going through with no ear protection what-so-ever. I would leave the live fire field unable to hear anything and a massive ringing in my ears. I trained with the Garand, a 30-06 rifle and the Government Model 1911 .45 semi automatic pistol. Being prone in the mud beside a Howitzer was no fun either.
Tillman
Chuck, you are doing everyone a disservice(particularly the gullible, willfully ignorant audiophiles) by spreading this nonsense. Please stop. There is no different between flac and wave, no difference between burn speeds...none of it. I promise. This type of stuff is why audiophiles get laughed at and ridiculed by those who actually know what is going on. Music is an art. AUDIO IS A SCIENCE. A WELL UNDERSTOOD SCIENCE(since the 30s!)
http://www.youtube.com/watch?v=BYTlN6wjcvQ
One more thing - I despise "Snake Oil"; that being said, one of my friend was extolling the benefit of "high-end" power cables. My attitude was "Bull Hockey".
The the SOB brought some over to try... well, I was shocked to notice an improvement when I expected absolutely none! Enough so that I now own three of the lower, higher end power cords. Go figure - they cannot possibly make a significant difference in theory.
So, how do they work? (Not a rhetorical question for the group.)
See my Beliefs article linked above for the explanation. You already posted that you understand how small changes in position can change what you hear. Swapping the power cord didn't change the sound, unless the original was defective which is doubtful. Also, have your friend test you blind. Then you'll know for sure.
--Ethan
I would even venture the quality of the computer to be valid. If you are using an old PC that is patched to death.... compared to a new PC or Mac with the latest software, chips.... virgin hard drive...... probably matters more than the cables do but in the end it all counts. Like making sure your discs are not scratched, dirty or cracked prior to ripping.
Here is the 2nd part to my FLAC vs WAV experiment I posted above:
http://www.computeraudiophile.com/blogs/FLAC-vs-WAV-Part-2-Final-Results
PS. JRiver vs JPLAY Test Results: http://www.computeraudiophile.com/blogs/JRiver-vs-JPLAY-Test-Results
I agree with the criticsm of the results regarding wav to flac to wav whole-heartedly.
However, as a Media Monkey user, I decided to try JRMC given that it was shown to be a better player for flac. Without adjusting Windows system volume, I was surprised to find that JRMC plays louder on my computer (Windows 7 64bit) than Media Monkey by a few db. So I tried Nero Showtime (already on my system) and Foobar. Foobar was similar to Media Monkey; Nero Showtime, more like JRMC.
Zeilig and Clawson wrote, "When appropriate, listening levels were matched to +/- 0.1dB. For most tests, this was unnecessary and redundant since common digital files yielded identical playback volumes." How did they level match the players? It could be done via Windows or by adjusting the volume on the amplifer/pre-amp post DAC conversion of the signal to analog. If the latter, well the PCM audio stream for the players with lower volume could have had some bit loss depending on how the volumes were set on Windows.
Whether or not this was a factor in the flac playback for different players is not the major issue (although it does cast doubts on their results). I don't understand why this writeup did not address this potenial variable. It makes it seem like the authors don't understand digital audio well enough to recognize this potential problem with their methodology.
Dr. Zeilig and Mr. Clawson: Congratulations on an excellent article series...these are very helpful. I have done some cursory testing; attempting some of the same experiments you describe. While I am just starting, I am getting similar responses you have documented. One question, the Samsung burner you cited has several variants...some of which seem to be out of production. Do you have more specific model number or an equivalent recommendation? Steven, any recommendations for an internal CD ripper/burner? I'm running a PC based on the Intel I-7 extreme Quad Core. One comment on my cursory tests, I notice a substantial difference between the Apple Lossless format and WAV...these difference are very similar those you describe in reference to the graphic on page 36 of issue 218. I'm hoping not to replicate this difference as this could cause me to re-rip...some not so small portion of my music collection, Thanks in advance!
Michael
Charles Zeilig's provocative article challenges some conventional wisdoms. Good, the debates have begun. Thank you Charles Zeilig for making all your findings very clear and in perspective with your quantitatively orientated approach using your sound quality scale and sound points awarded method. Here's looking forward to your next article on the subject. So impressed am I with the scope and effort put into this research that I have many comments.
For one thing, the FLAC inferiority/WAV superiority issue, which is taking stage center in debate, is important to music consumers. No one wants to have paid up to $30 for a FLAC digital download only to learn later that WAV is superior. Those of us who have evolved over the years with The Rolling Stones on LP, CD, remastered CD, hybrid SACD, and 16/44 kHz and 24/196 kHz digital FLAC downloads can relate to that. I'll bet that this one doesn't get decided anytime soon though.
The FLAC vs. WAV debate is closely tied to the classic bits-is-bits argument. But let's not lose sight that Zeilig raises other important issues as well which aren't so much about bits-is-bits. In that spirit, here are some of his other findings with my humble comments:
1) Zeilig says upsampling software programs like iZotope improve sound quality which increases as upsampling rates increase. Also, some programs outperform others. Comment: conventional wisdom has it that upsampling changes the music artificially, so the sound is not improved or is even harmed; and those who claim to hear an improvement are the odd exception with listening tastes that just happen to match up with the artificial sound. Given this, the finding is a food-for-thought surprise indeed.
2) Some music player programs outperform others. For instance, Foobar 2000 and JRMC rated higher than iTunes. JPlay, a program that plays on top of iTunes, has one of the highest sound quality scores. Comment: Many think that iTunes on PC doesn't sound as good as iTunes on Apple Mac because of the native environment thing and because iTunes on PC can't bypass Apple's Quicktime Music Synthesizer which doesn't do as well on a PC as a Mac. It's generally accepted that music player programs are not created equal. Just why this is so is less clear, but here's guessing that the devil is deep in the inevitable programming decisions, trade-offs, and goals.
3) Tweaking apparently has as much a place in the computer audio world as in the analog world. For instance, Zeilig finds improvements by changing the Canare S/PDIF coaxial 25 ft. cable to a Kimber KS-2020 S/PDIF coaxial 0.75m cable; by isolating the PC on a granite shelf with isolation feet; and as Zeilig said, "the largest improvement occurred when we replaced the standard computer power cord with a top-quality PS Audio Statement cable retailing for $500." That's computer power cord! We heard it here first folks.
4) Zeilig found that breaking the S/PDIF ground connection with an isolation transformer improved the sound. Comment: this seems consistent with other experts' advice that DACs and USB-to-S/PDIF converters be engineered with "galvanic isolation" for improved sound.
5) And this one is a real surprise - removing from the PC a video connection to an LCD front projector had a large improvement. Another smaller improvement was had by removing the USB connections from the PC. Comment: this finding begs to be researched further. Understanding the why of this could also help us understand better other dark, mysterious areas of using a computer as a music maker. Even if computer video connections cause noise and jitter, how the heck can it manage to get past asynchronous DACs with galvanic isolation and all the way to our ears?
6) Ripping CD's to WAV is not created equal: dBpoweramp outperformed all other programs and, ouch, it bested the popular EAC and iTunes rippers. Ripping is at the beginning of the chain so if you have a sub-optimal rip, it's set in concrete, and the only way to fix it is to go back and re-rip. Knowing that EAC and iTunes are very popular, this finding must raise anxieties.
Zeilig obviously put a lot of effort into this research project. That said, on a critical note, the PC's USB port was ignored and only 192 kHz capable internal sound cards and their S/PDIF coaxial ports were used in the two test systems (and sound card brand names weren't mentioned darn it). This is disappointing given that many audiophiles are using PC or Mac laptops or Mac Minis that can't fit a sound card and so are likely using the USB port. Maybe next time.
By the way, what is this gentleman's background and audio industry experience? Hey, Absolute Sound, attaching a guest contributor bio to an article like this would be helpful to readers.
absolute twaddle. I can only guess they do it to keep afloat the snake oil/foo/hokum hifi industry.
FLAC is equal to WAV. Bits are bits. The DAC does not give a damn about what source it comes from. people PLEASE PLEASE educate yourselves.
here are some very good books to get the basics..
http://www.amazon.com/Mastering-Audio-Science-Bob-Katz/dp/0240805453
http://www.amazon.com/Digital-Audio-Explained-Engineer/dp/141960001X/ref...
http://www.amazon.com/Principles-Digital-Audio-Sixth-Video/dp/0071663460...
http://www.amazon.com/gp/offer-listing/0387284702/ref=dp_olp_used?ie=UTF...
educate yourselves and stop supporting counterintuitive, IMPOSSIBLE, FALSE ideas and MYTHS!