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44.1 vs 88.2 ABX report at AES
2Bdecided
post Jul 16 2010, 17:07
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Here:

http://www.aes.org/events/128/papers/?ID=2252

QUOTE
P18-6 Sampling Rate Discrimination: 44.1 kHz vs. 88.2 kHz—Amandine Pras, Catherine Guastavino, McGill University - Montreal, Quebec, Canada
It is currently common practice for sound engineers to record digital music using high-resolution formats, and then down sample the files to 44.1 kHz for commercial release. This study aims at investigating whether listeners can perceive differences between musical files recorded at 44.1 kHz and 88.2 kHz with the same analog chain and type of AD-converter. Sixteen expert listeners were asked to compare 3 versions (44.1 kHz, 88.2 kHz, and the 88.2 kHz version down-sampled to 44.1 kHz) of 5 musical excerpts in a blind ABX task. Overall, participants were able to discriminate between files recorded at 88.2 kHz and their 44.1 kHz down-sampled version. Furthermore, for the orchestral excerpt, they were able to discriminate between files recorded at 88.2 kHz and files recorded at 44.1 kHz.
Convention Paper 8101


Was anyone at the presentation? Has anyone bought the paper?

Cheers,
David.
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Cavaille
post Jul 20 2010, 08:40
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Forgive me to interrupt this discussion about the Fireface 800 (which seems to be a decent interface - or does it contain another matter?!?) but I have a question.

Arnie, you suggested to improve this test by upsampling the downsampled material to the samplerate the original had. I very much see the logic in your suggestion. However, may it be that brick wall filtering could introduce audible obstacles into the signal that are unwanted? I´m referring to the thread "Audibility of 20kHz brick wall filtering". So far (only three people have participated, including me) it seems that brick wall filtering may be audible. Further tests by several people are required however. And it is my impression that both downsampling & upsampling use brick wall filtering to avoid aliasing artifacts for downsampling and imaging products for upsampling. Is that assumption correct?

So, if I´m using brick wall filtering two times, wouldn´t that be even more audible? Or am I getting this wrong?


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Arnold B. Kruege...
post Jul 20 2010, 13:13
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QUOTE (Cavaille @ Jul 20 2010, 03:40) *
Arnie, you suggested to improve this test by upsampling the downsampled material to the samplerate the original had. I very much see the logic in your suggestion. However, may it be that brick wall filtering could introduce audible obstacles into the signal that are unwanted?


I think that the audibility of brick wall filtering in the downsampling is the actual object of the test.

QUOTE
I´m referring to the thread "Audibility of 20kHz brick wall filtering". So far (only three people have participated, including me) it seems that brick wall filtering may be audible. Further tests by several people are required however.


If I understand that test properly, it has a serious limitation - the program material being used is implulses, not real world music. Even impulsive sounds in music far fall short of the extreme spectral content of a steady stream of impulses. Listening to impulses is about as much fun as listening to white noise.

QUOTE
And it is my impression that both downsampling & upsampling use brick wall filtering to avoid aliasing artifacts for downsampling and imaging products for upsampling. Is that assumption correct?


It is my understanding that downsampling uses brick wall filtering, but that upsampling either uses no brick wall filtering at all, or uses brick wall filtering at the nyquist frequency of the higher sample rate. It is very hard to avoid brick wall filtering in digital, so that's rarely the goal. As I understand it, the major goal of higher sample rates is raising the frequency of any brick wall filters.

QUOTE
So, if I´m using brick wall filtering two times, wouldn´t that be even more audible? Or am I getting this wrong?


I think that the frequency of the corner frequency of the brick walls is highly significant. I don't think that anybody disagrees with the idea that in general, the higher the better. The only questions I'm aware of are how high, and what phase response is required for sonic transparency.
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WernerO
post Aug 2 2010, 08:19
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QUOTE (Arnold B. Krueger @ Jul 20 2010, 14:13) *
It is my understanding that downsampling uses brick wall filtering, but that upsampling either uses no brick wall filtering at all, or uses brick wall filtering at the nyquist frequency of the higher sample rate. It is very hard to avoid brick wall filtering in digital, so that's rarely the goal. As I understand it, the major goal of higher sample rates is raising the frequency of any brick wall filters.

I think that the frequency of the corner frequency of the brick walls is highly significant. I don't think that anybody disagrees with the idea that in general, the higher the better. The only questions I'm aware of are how high, and what phase response is required for sonic transparency.


Your understanding is wrong. In fact so fundamentally wrong that I urge you to re-assess your complete knowledge of signal theory and of the sampling theorem.

Up- and oversampling still are both terms for the same mathematical process, and if that process is executed with the intent to obey the sampling theorem (i.e. contrary to doing funny stuff for the sake of it), then it will include a brickwall filter at half the original sampling rate. It simply has to, as this constitutes the bulk of that signal's reconstruction.

When oversampling the goal is not to raise the cutoff frequency of the brickwall (reconstruction) filter. That cutoff has to remain at half the original rate, as otherwise the first images are allowed to creep out. The goal, at least for a DAC, is to make most of the reconstructor in the digital domain (i.e. cheap, steep, linear, and linear-phase), with only the remainder in the analogue domain (there to suppress the images of the oversampled signal), indeed potentially at a higher cut-off frequency and with a shallow slope (i.e. cheap and simple).


It is similar in ADCs, where the modulator runs at several MHz and hard aliasing can be avoided with a simple analogue filter cutting in at a couple of 100kHz (which does not mean that designing analogue front-ends for today's DS ADCs is simple). After the conversion in the low-bit modulator the signal is then noise-shaped and decimated, which (ignoring the noise shaping) comprises of brickwall anti-alias filtering at the target Nyquist frequency.

In this sense running a Delta-Sigma ADC at 44.1kHz is the same as running it at 88.2kHz followed with off-line downsampling. The only difference is in the implementation of the two (actuall three!) anti-alias filters involved, where the off-line solution can be of arbitrarily high quality, while the hardware solution often is not that good at all. Indeed, most commercial ADC chips use half-band AA filters and thus allow some aliasing to happen in the, say, 20-22kHz band.




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Arnold B. Kruege...
post Aug 2 2010, 11:56
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QUOTE (WernerO @ Aug 2 2010, 03:19) *
QUOTE (Arnold B. Krueger @ Jul 20 2010, 14:13) *
It is my understanding that downsampling uses brick wall filtering, but that upsampling either uses no brick wall filtering at all, or uses brick wall filtering at the nyquist frequency of the higher sample rate. It is very hard to avoid brick wall filtering in digital, so that's rarely the goal. As I understand it, the major goal of higher sample rates is raising the frequency of any brick wall filters.

I think that the frequency of the corner frequency of the brick walls is highly significant. I don't think that anybody disagrees with the idea that in general, the higher the better. The only questions I'm aware of are how high, and what phase response is required for sonic transparency.


Your understanding is wrong. In fact so fundamentally wrong that I urge you to re-assess your complete knowledge of signal theory and of the sampling theorem.


Right and this was all corrected a week ago. Read on...
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Posts in this topic
- 2Bdecided   44.1 vs 88.2 ABX report at AES   Jul 16 2010, 17:07
- - Dologan   Interesting. The fact that the discrimination was ...   Jul 16 2010, 18:18
|- - C.R.Helmrich   http://coltrane.music.mcgill.ca/MAQ/experiments co...   Jul 16 2010, 19:33
|- - Dologan   QUOTE (C.R.Helmrich @ Jul 16 2010, 19:33)...   Jul 16 2010, 20:30
- - Arnold B. Krueger   QUOTE (2Bdecided @ Jul 16 2010, 12:07) He...   Jul 16 2010, 19:45
|- - pbelkner   QUOTE (Arnold B. Krueger @ Jul 16 2010, 20...   Jul 16 2010, 20:01
||- - Dologan   QUOTE (pbelkner @ Jul 16 2010, 20:01) QUO...   Jul 16 2010, 20:03
||- - pbelkner   QUOTE (Dologan @ Jul 16 2010, 21:03) but ...   Jul 16 2010, 20:19
||- - benski   Yes, exactly. It is cheaper to design a 192kHz DA...   Jul 16 2010, 20:47
||- - Arnold B. Krueger   QUOTE (Dologan @ Jul 16 2010, 15:03) QUOT...   Jul 16 2010, 23:21
|- - C.R.Helmrich   QUOTE Overall, participants were able to discrimin...   Jul 16 2010, 20:25
|- - pbelkner   QUOTE (C.R.Helmrich @ Jul 16 2010, 21:25)...   Jul 16 2010, 20:59
- - krabapple   1) I suggest this thread be focused on the 44.1 v...   Jul 16 2010, 22:23
|- - WernerO   QUOTE (krabapple @ Jul 16 2010, 23:23) Th...   Aug 11 2010, 13:51
|- - mzil   QUOTE (krabapple @ Jul 16 2010, 17:23) 2)...   Jul 22 2012, 02:47
|- - C.R.Helmrich   Sorry for bumping this thread, but I thought the f...   Mar 8 2014, 01:21
|- - [JAZ]   QUOTE (C.R.Helmrich @ Mar 8 2014, 01:21) ...   Mar 8 2014, 18:38
- - googlebot   Why upsample? 99.9% of all DACs oversample anyway....   Jul 16 2010, 22:25
|- - Arnold B. Krueger   QUOTE (googlebot @ Jul 16 2010, 17:25) Wh...   Jul 16 2010, 23:47
|- - benski   QUOTE (Arnold B. Krueger @ Jul 16 2010, 18...   Jul 17 2010, 03:12
||- - Arnold B. Krueger   QUOTE (benski @ Jul 16 2010, 22:12) QUOTE...   Jul 17 2010, 06:39
||- - greynol   QUOTE (Arnold B. Krueger @ Jul 16 2010, 22...   Jul 17 2010, 18:33
||- - Arnold B. Krueger   QUOTE (greynol @ Jul 17 2010, 13:33) QUOT...   Jul 17 2010, 20:35
|- - 2Bdecided   QUOTE (Arnold B. Krueger @ Jul 16 2010, 23...   Jul 21 2010, 13:22
- - Alex B   I think the least incorrect way to compare 88.2 KH...   Jul 16 2010, 22:33
|- - Arnold B. Krueger   QUOTE (Alex B @ Jul 16 2010, 17:33) I thi...   Jul 16 2010, 23:30
|- - Dologan   QUOTE (Alex B @ Jul 16 2010, 22:33) I thi...   Jul 16 2010, 23:40
- - AndyH-ha   It seems that what I wrote in the first part of my...   Jul 17 2010, 09:55
|- - googlebot   AndyH-ha, that might be on purpose. For two lowpas...   Jul 17 2010, 10:49
- - googlebot   I think the 88.2 vs. downsampled 44.1 test had at ...   Jul 17 2010, 16:39
- - greynol   QUOTE (Arnold B. Krueger @ Jul 17 2010, 12...   Jul 17 2010, 20:48
|- - Arnold B. Krueger   QUOTE (greynol @ Jul 17 2010, 15:48) QUOT...   Jul 17 2010, 23:04
- - AndyH-ha   I also may not know what I'm talking about, bu...   Jul 17 2010, 22:02
- - greynol   The reason for oversampling in old CD players is a...   Jul 17 2010, 22:13
|- - Arnold B. Krueger   QUOTE (greynol @ Jul 17 2010, 17:13) The ...   Jul 17 2010, 23:14
- - greynol   I'm taking issue with what I thought was a bla...   Jul 17 2010, 23:27
|- - Arnold B. Krueger   QUOTE (greynol @ Jul 17 2010, 18:27) I...   Jul 18 2010, 01:52
|- - greynol   QUOTE (Arnold B. Krueger @ Jul 17 2010, 17...   Jul 19 2010, 00:56
- - amandinepras   Thanks all for your interest in our paper, I recei...   Jul 19 2010, 00:52
|- - Arnold B. Krueger   QUOTE (amandinepras @ Jul 18 2010, 19:52)...   Jul 19 2010, 03:35
|- - Arnold B. Krueger   QUOTE (amandinepras @ Jul 18 2010, 19:52)...   Jul 19 2010, 11:35
||- - 2Bdecided   QUOTE (Arnold B. Krueger @ Jul 19 2010, 11...   Jul 21 2010, 13:20
||- - Kees de Visser   QUOTE (2Bdecided @ Jul 21 2010, 14:20) QU...   Jul 23 2010, 09:26
|- - Arnold B. Krueger   QUOTE (amandinepras @ Jul 18 2010, 19:52)...   Jul 19 2010, 11:48
||- - googlebot   QUOTE (Arnold B. Krueger @ Jul 19 2010, 12...   Jul 19 2010, 12:19
|||- - Arnold B. Krueger   QUOTE (googlebot @ Jul 19 2010, 07:19) QU...   Jul 19 2010, 14:33
||- - krabapple   QUOTE (Arnold B. Krueger @ Jul 19 2010, 06...   Jul 19 2010, 14:08
|- - Notat   QUOTE (amandinepras @ Jul 18 2010, 17:52)...   Jul 21 2010, 04:08
|- - hciman77   QUOTE (amandinepras @ Jul 18 2010, 19:52)...   Jul 28 2010, 15:18
- - Pio2001   Thanks for joining the discussion, Amandine. Your...   Jul 19 2010, 12:31
|- - 2Bdecided   QUOTE (Pio2001 @ Jul 19 2010, 12:31) I se...   Jul 21 2010, 13:13
- - googlebot   The study shows at least the intent of objectivity...   Jul 19 2010, 16:28
|- - Arnold B. Krueger   QUOTE (googlebot @ Jul 19 2010, 11:28) [l...   Jul 19 2010, 19:11
|- - Soap   QUOTE (Arnold B. Krueger @ Jul 19 2010, 14...   Jul 19 2010, 20:24
|- - Soap   QUOTE (Arnold B. Krueger @ Jul 19 2010, 14...   Jul 19 2010, 23:07
- - Juha   QUOTE Doesn't anybody else see a problem with ...   Jul 19 2010, 19:25
- - googlebot   The manufacturer's specs for the FF 800. Unwei...   Jul 19 2010, 20:22
|- - Arnold B. Krueger   QUOTE (googlebot @ Jul 19 2010, 15:22) Th...   Jul 19 2010, 21:26
- - Cavaille   Forgive me to interrupt this discussion about the ...   Jul 20 2010, 08:40
|- - Arnold B. Krueger   QUOTE (Cavaille @ Jul 20 2010, 03:40) Arn...   Jul 20 2010, 13:13
|- - Arnold B. Krueger   QUOTE (Arnold B. Krueger @ Jul 20 2010, 08...   Jul 20 2010, 19:30
||- - Pio2001   QUOTE (Arnold B. Krueger @ Jul 20 2010, 20...   Jul 20 2010, 22:36
|||- - Arnold B. Krueger   QUOTE (Pio2001 @ Jul 20 2010, 17:36) QUOT...   Jul 20 2010, 23:57
||- - C.R.Helmrich   QUOTE (Arnold B. Krueger @ Jul 20 2010, 20...   Jul 20 2010, 22:53
|- - 2Bdecided   QUOTE (Arnold B. Krueger @ Jul 20 2010, 13...   Jul 21 2010, 13:25
|- - WernerO   QUOTE (Arnold B. Krueger @ Jul 20 2010, 14...   Aug 2 2010, 08:19
|- - Arnold B. Krueger   QUOTE (WernerO @ Aug 2 2010, 03:19) QUOTE...   Aug 2 2010, 11:56
- - Pio2001   The strange thing is that there are ABX results wi...   Jul 21 2010, 12:16
|- - hciman77   QUOTE (Pio2001 @ Jul 21 2010, 07:16) The ...   Jul 27 2010, 22:56
- - googlebot   The fact, that the study's authors have regist...   Jul 23 2010, 10:55
|- - Pio2001   QUOTE (googlebot @ Jul 23 2010, 11:55) co...   Jul 24 2010, 13:58
- - krabapple   Sheesh, it's only been four days. They may ac...   Jul 23 2010, 19:20
- - googlebot   In dubio pro reo is generally a good principle. Bu...   Jul 26 2010, 19:43
|- - hciman77   QUOTE (googlebot @ Jul 26 2010, 14:43) In...   Jul 26 2010, 21:05
- - hciman77   I read the full paper and I think there may be som...   Jul 26 2010, 19:48
|- - Arnold B. Krueger   QUOTE (hciman77 @ Jul 26 2010, 14:48) I r...   Jul 27 2010, 13:16
||- - 2Bdecided   QUOTE (Arnold B. Krueger @ Jul 27 2010, 13...   Jul 27 2010, 22:45
|- - Pio2001   QUOTE (hciman77 @ Jul 26 2010, 20:48) Thi...   Jul 28 2010, 11:39
|- - Arnold B. Krueger   QUOTE (Pio2001 @ Jul 28 2010, 06:39) QUOT...   Jul 28 2010, 13:52
|- - AndyH-ha   QUOTE (Arnold B. Krueger @ Jul 28 2010, 04...   Jul 28 2010, 22:42
|- - Arnold B. Krueger   QUOTE (AndyH-ha @ Jul 28 2010, 17:42...   Jul 29 2010, 13:04
|- - 2Bdecided   QUOTE (AndyH-ha @ Jul 28 2010, 22:42...   Jul 29 2010, 22:11
|- - SebastianG   QUOTE (2Bdecided @ Jul 29 2010, 22:11) bu...   Jul 30 2010, 09:55
|- - Arnold B. Krueger   QUOTE (2Bdecided @ Jul 29 2010, 17:11) I ...   Jul 30 2010, 12:26
- - lvqcl   Audition 1.5: 44.1 -> 96 kHz resampling, Qualit...   Jul 30 2010, 11:42
- - C.R.Helmrich   I finally found time to read the entire paper. It...   Aug 9 2010, 21:41
- - 2Bdecided   I think before you pull out one positive result an...   Aug 9 2010, 22:44
|- - C.R.Helmrich   QUOTE (2Bdecided @ Aug 9 2010, 23:44) I t...   Aug 10 2010, 01:37
- - Pio2001   I finaly got the article. Actually, they say somet...   Aug 9 2010, 23:33
- - Pio2001   The unknown thing is the origin of the p values. I...   Aug 10 2010, 12:33
- - lrossouw   Did they test for difference (Check if you can tel...   Sep 8 2010, 09:39
- - Mach-X   I am going to loosely quote a well known poster he...   Mar 8 2014, 08:08
|- - Arnold B. Krueger   QUOTE (Mach-X @ Mar 8 2014, 03:08) I...   Mar 10 2014, 12:58
- - bandpass   TEAC -- slight COI perhaps? Guessing their method...   Mar 8 2014, 09:06
- - WernerO   Perhaps. Another weakness is their apparent use o...   Mar 11 2014, 08:04
|- - Arnold B. Krueger   QUOTE (WernerO @ Mar 11 2014, 03:04) Perh...   Mar 11 2014, 13:44
||- - Kees de Visser   QUOTE (Arnold B. Krueger @ Mar 11 2014, 13...   Mar 11 2014, 14:28
|- - C.R.Helmrich   QUOTE (WernerO @ Mar 11 2014, 08:04) Anot...   Mar 11 2014, 23:55
- - Wombat   QUOTE (Kees de Visser @ Mar 11 2014, 14:2...   Mar 11 2014, 15:51
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