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The Absolute Sound FLAC article
SoAnIs
post Jan 7 2012, 04:19
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My father subscribes to "The Absolute Sound," and in the latest issue they have an article about FLAC. Of course they have no (or very minimal) double-blind testing (something both my father and I believe is necessary for any review to be valid) and a history of endorsing bullshit, so we take their results with a truckload of salt.
They score their comparisons on a scale from 0-200 points, with CD audio as 100 points. The scores are generated by A/B comparison (not A/B/X) to a variety of reference qualities. The first issue crops up with this. 0 = Kazoo. 50 = 320kbps MP3. 100 = Red Book CD, 44.1khz/16 bit. 110 = 48khz/24 bit upconverted CD. 120 = 88/24 upconverted. 130 = 96/24 upconverted. 150 = 176/24 upconverted. 160 = 192/24 upconverted. 170 = 192/32 upconverted. 180 = SACD/HRx/High-res downloads. 200 = "Master Tape?". There are no references between 50 and 100. Furthermore, a "very large" difference of 50 points would "require only one A/B comparison and is so large that a 24-hour hiatus between listening sessions would still elicit the typical audiophile expression of 'Holy Cow! This is a night and day difference!'"
Both their reference systems used on-board sound cards capable of 192khz S/PDIF output into a PS Audio PWD DAC. Motherboard brand and model is not disclosed. Actual sound-card model is not disclosed.
This seems quite suspicious to me. I have been unable to successfully detect differences between 320kbps CBR MP3, wave ripped from CD using Exact Audio Copy, and CD Audio using Foobar2000's ABX comparator plugin. I used Epica's "Design Your Universe" tracks "White Waters" and "Burn to a Cinder" as my references this time. I used the onboard audio of my motherboard (an ASUS P6X58D Premium, Realtek ALC889 audio, with 24-bit/192khz default output set in Windows 7) and a set of Grado SR-60 stereo headphones. My CD drive is a Lite-On iHAS424. I don't have a fancy $4000 DAC. My ABX test results were no better than guessing, nowhere near a "night and day" difference audible with a 24-hour gap. I sincerely doubt that the lower quality of my headphones and DAC would be enough to mask such a difference. Thus, I doubt their measurement scale's accuracy.
They did their playback comparisons using JRMC (proprietary) with 192/32 realtime upsampling. They never once mention using the reference FLAC encoder/decoder, or even FLAC frontend.
The top 3 programs in sound quality were:
JRMC: 150 score for HRx 176.1khz/24-bit to FLAC
dBPowerAmp: 145
Foobar2000: 140
Original HRx wave file: 180
So they're claiming a large drop in sound quality.
Later they claim that converting from FLAC to WAV with Foobar can increase sound quality (where would the extra data be coming from?) and that other programs decrease sound quality. In all cases they claim a decrease in sound quality when compared to the original CD.
They also (via listening tests, no md5 hashing or such) claim that Wav->FLAC->Wav conversions create cumulative degradation. This is, of course, a very big claim.
So I took a wav file (a rip of "White Waters", mentioned above) and used the FLAC reference encoder to compress it. Then to decompress. I compared the MD5 hashes of the two .wav files, and they were the same. Just in case some strange miracle had occurred and I'd found an MD5 collision I compared the SHA-512 sums, and those were also the same. The two files were bit-for-bit identical. Just for fun, I repeated the wav->FLAC->wav process 10 times, and the files still had identical hashes. I then ABX tested the original and final files, and was unable to do better than guessing.

TL;DR: Bullshit detected.
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oldguy55
post Jan 11 2012, 03:59
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The article happens to be part 2 of a 4-part series. The first installment went to great length to describe the test equipment and methods used, and explained all the questions they were going to try to answer. I think this is what I'm looking for, a comprehensive examination of digital audio, as it sits today, so I can know which tools to use, and the difference in the various formats that can be used to store and play back my audio collection. I haven't seen this installment, yet, but I'm sure that if the person who started this thread had been paying attention, they would have seen that it was part 2 of a series. They need to go back an issue, and come up to speed, because it's way too early in the series to be calling them out on their findings, as they're only halfway through the article. Anything less is what I call B.S.. By the way, I'm not a big fan of those guys, because I'm sick of in depth reviews of $5K dacs and $25K speaker systems, since the great majority of people anywhere can't even dream of owning that gear, and I find it to be elitist, IMHO, but sometimes they do teach me about audio, and we should let them finish this lesson, before we start running them down, I think.
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Posts in this topic
- SoAnIs   The Absolute Sound FLAC article   Jan 7 2012, 04:19
- - testyou   FLAC is Lossless. What are you asking about?   Jan 7 2012, 04:41
- - A_Man_Eating_Duck   I struggle to read what you have posted any chance...   Jan 7 2012, 05:03
- - SoAnIs   I'm not asking anything. I'm describing th...   Jan 7 2012, 06:22
|- - Charlie Freak   I couldn't find that article on their website,...   Jan 7 2012, 07:12
|- - mjb2006   QUOTE (Charlie Freak @ Jan 6 2012, 23:12)...   Jan 7 2012, 07:31
- - MichaelW   The simple answer is that your father should no lo...   Jan 7 2012, 07:14
- - SoAnIs   Yep. The funniest bit is that none of the audiophi...   Jan 7 2012, 07:31
|- - zappalberto   QUOTE (SoAnIs @ Jan 7 2012, 07:31) Yep. T...   Nov 6 2013, 17:39
- - db1989   I’d compare this to shooting fish in a barrel—but ...   Jan 7 2012, 13:12
|- - Nessuno   QUOTE (db1989 @ Jan 7 2012, 13:12) I coul...   Jan 7 2012, 13:47
- - Speedskater   This is the third article in a four part series. ...   Jan 7 2012, 15:43
- - Apesbrain   "0 = Kazoo." Bummer. I play the kazoo ...   Jan 7 2012, 16:02
|- - SoAnIs   QUOTE (Apesbrain @ Jan 7 2012, 07:02) ...   Jan 9 2012, 21:40
- - ramicio   Is this the same article which claims that the spe...   Jan 9 2012, 21:58
|- - Porcus   QUOTE (ramicio @ Jan 9 2012, 21:58) Is th...   Jan 9 2012, 22:27
|- - ramicio   QUOTE (Porcus @ Jan 9 2012, 17:27) Of cou...   Jan 11 2012, 14:20
- - db1989   Yeah, from the same series. Sorry, I meant epic sa...   Jan 9 2012, 22:01
- - oldguy55   The article happens to be part 2 of a 4-part serie...   Jan 11 2012, 03:59
|- - krabapple   QUOTE (oldguy55 @ Jan 10 2012, 21:59) The...   Jan 11 2012, 06:03
|- - krabapple   QUOTE (krabapple @ Jan 11 2012, 00:03) An...   Jan 13 2012, 00:32
- - greynol   That reminds me about the time someone suggested t...   Jan 11 2012, 05:02
- - krabapple   QUOTE (SoAnIs @ Jan 6 2012, 22:19) 0 = Ka...   Jan 11 2012, 06:11
- - 2Bdecided   apparently part 3 is even better... QUOTE The art...   Jan 11 2012, 11:24
- - polemon   The fact that FLAC is lossless, and should always ...   Jan 11 2012, 11:28
|- - krabapple   QUOTE (polemon @ Jan 11 2012, 05:28) The ...   Jan 13 2012, 00:06
|- - polemon   QUOTE (krabapple @ Jan 13 2012, 00:06) um...   Jan 13 2012, 16:03
- - Satellite_6   Very amusing. Doesn't it seem like more than...   Jan 13 2012, 02:13
- - Wombat   I wonder if this things that TAS testers hear is t...   Jan 13 2012, 19:32
|- - PeterJvM   QUOTE (Wombat @ Jan 13 2012, 20:32) I won...   Jan 15 2012, 12:22
- - ron spencer   What is the motivation of this article? I must ad...   Jan 13 2012, 21:14
|- - slks   QUOTE (ron spencer @ Jan 13 2012, 14:14) ...   Jan 15 2012, 11:04
- - Squeller    If, with good gear and ears people could hear dif...   Jan 14 2012, 15:44
- - milosz   I agree that two bit-identical files should sound ...   Jan 18 2012, 20:47
|- - probedb   QUOTE (milosz @ Jan 18 2012, 19:47) What ...   Jan 19 2012, 10:24
|- - bug80   QUOTE (milosz @ Jan 18 2012, 20:47) What ...   Jan 19 2012, 10:38
||- - DonP   QUOTE (bug80 @ Jan 19 2012, 05:38) QUOTE ...   Jan 19 2012, 15:00
||- - bug80   QUOTE (DonP @ Jan 19 2012, 15:00) QUOTE (...   Jan 19 2012, 15:11
|- - Brother John   QUOTE (milosz @ Jan 18 2012, 20:47) What ...   Jan 20 2012, 12:02
- - Wombat   QUOTE (milosz @ Jan 18 2012, 20:47) I agr...   Jan 18 2012, 21:14


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