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What's the problem with double-blind testing?
mirrorsawlljk
post Oct 19 2005, 03:03
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I happened to pick up an issue of stereophile at a record store I visited and I was pretty shocked to see a seemingly intelligent person in the correspondence section bashing double blind testing as being unreliable. I'm afraid I don't understand his angle of attack. I don't see how anything could be a more reliable test of sound quality differences than a properly conducted double blind listening test.

I'm almost afraid to read the rest of the magazine if this is the kind of letter they think is worth publishing. Is there an audio magazine that isn't filled with this kind of thinking?
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duff
post Oct 22 2005, 00:30
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QUOTE
It sounds counterintuitive that my brain would have to work harder on a lossy compressed signal than on the original. Also note that duff and you are not helping each other, because you say the brain needs to work harder to filter out the noise, and duff says the brain needs to work harder to somehow interpolate the signal and thus creating info.


Filtering and unconscious inference processes take place in the brain on all sinusoidal waves (light and sound). These processes are taxed by noise.

QUOTE
This is also what isn't debated. Audible differences lie within the scope of an ABX-test.


David's example addressed the contention that noisy stimuli aren't harder to process. Why would this principle change just because the noise isn't audible? Again, you need to separate the processing from the product of that processing (i.e., the percept).

QUOTE
When people start using phrases like "It goes without saying" and "uncontroversial" I always immediately start asking myself: "Is that so?".


Frankly, I find it surprising that I need to convince people that degraded signals require more effort to process. This is not the speculative element of the idea. But I understand that our use of the term "effort" is not one people ordinarily consider. I will provide examples of research demonstrating this soon.
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ChiGung
post Oct 22 2005, 00:47
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QUOTE (duff @ Oct 22 2005, 12:30 AM)
Frankly, I find it surprising that I need to convince people that degraded signals require more effort to process. This is not the speculative element of the idea. But I understand that our use of the term "effort" is not one people ordinarily consider. I will provide examples of research demonstrating this soon.
*

Because they arent 'degraded' - they are changed and filtered. They arent 'messier', maybe they are notably artificial in respects but - if you are used to refering to the necessarily perceptibly subtle changes allowed by lossy encoding, with perjorative terms as degrade and elsewhere 'impoverished' you'll have a problem with seeing them fairly. That a perceptibly subtle change can be 'strong' or 'powerful' doesnt mean its 'noisy' just different. Im open to the idea there are unconcious differences in their perception, and maybe some unconcious stresses to watch out for in psychoacoustics, but different sound doesnt have to be messier sound.


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duff
post Oct 22 2005, 01:14
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QUOTE (ChiGung @ Oct 21 2005, 11:47 PM)
QUOTE (duff @ Oct 22 2005, 12:30 AM)
Frankly, I find it surprising that I need to convince people that degraded signals require more effort to process. This is not the speculative element of the idea. But I understand that our use of the term "effort" is not one people ordinarily consider. I will provide examples of research demonstrating this soon.
*

Because they arent 'degraded' - they are changed and filtered. They arent 'messier', maybe they are notably artificial in respects but - if you are used to refering to the necessarily perceptibly subtle changes allowed by lossy encoding, with perjorative terms as degrade and elsewhere 'impoverished' you'll have a problem with seeing them fairly. That a perceptibly subtle change can be 'strong' or 'powerful' doesnt mean its 'noisy' just different. Im open to the idea there are unconcious differences in their perception, and maybe some unconcious stresses to watch out for in psychoacoustics, but different sound doesnt have to be messier sound.
*



The reduction of resolution and introduction of noise into a signal, to my mind, qualifies as a degradation. That's what lossy encoders do. I use this in a technical sense, so I don't mean to disparage any lossy format with "pejorative" intentions! Bad mp3 file! Bad!
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ChiGung
post Oct 22 2005, 01:26
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QUOTE (duff @ Oct 22 2005, 01:14 AM)
The reduction of resolution and introduction of noise into a signal, to my mind, qualifies as a degradation. That's what lossy encoders do. I use this in a technical sense, so I don't mean to disparage any lossy format with "pejorative" intentions! Bad mp3 file! Bad!

I know you dont mean that, but you are placing the change in sound in an troublesome context with the terms, when the change is virtualy sculpted as best it can to result in no perceptible troubles. I think it is only an added noise in one abstract sense, fundamentaly its just a change.

When we listen to a difference track, we hear a jumbled up compound of lots of individual differences, and it sounds bad, but we are not percieving them in context, in their context they were (at least consciously) imperceptable. In their context they are ratios, they are the details of a relationship between one sound and another. Relating to them as the medium which they reference is misleading. wacko.gif

This post has been edited by ChiGung: Oct 22 2005, 01:43


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Posts in this topic
- mirrorsawlljk   What's the problem with double-blind testing?   Oct 19 2005, 03:03
- - bubka   some people can actually detect specific codecs by...   Oct 19 2005, 03:07
- - TheQat   QUOTE (mirrorsawlljk @ Oct 18 2005, 06:03 PM)...   Oct 19 2005, 03:27
|- - singaiya   QUOTE (TheQat @ Oct 18 2005, 06:27 PM)QUOTE (...   Oct 19 2005, 04:31
|- - Yaztromo   QUOTE (TheQat @ Oct 19 2005, 03:27 AM)Edit: H...   Oct 19 2005, 23:05
- - Tahnru   The closest thing I have seen to a legitimate crit...   Oct 19 2005, 04:29
- - Axon   The Audio Critic is notably pro-DBT.   Oct 19 2005, 07:06
|- - PoisonDan   QUOTE (Axon @ Oct 19 2005, 08:06 AM)The Audio...   Oct 19 2005, 12:18
- - onthejazz   Interesting publication. I like it, too bad its no...   Oct 19 2005, 10:03
|- - Donunus   The writer of the letter in stereophile is incorre...   Oct 19 2005, 11:00
|- - Danimal   QUOTE (Donunus @ Oct 19 2005, 05:00 AM)The wr...   Oct 19 2005, 20:20
|- - Donunus   QUOTE (Danimal @ Oct 20 2005, 03:20 AM)QUOTE ...   Oct 20 2005, 01:51
|- - stephanV   QUOTE (Donunus @ Oct 20 2005, 02:51 AM)Well, ...   Oct 20 2005, 08:48
||- - bryant   QUOTE (stephanV @ Oct 19 2005, 11:48 PM)QUOTE...   Oct 20 2005, 18:11
|||- - Pio2001   QUOTE (bryant @ Oct 20 2005, 07:11 PM)To tell...   Oct 20 2005, 20:48
||||- - singaiya   Thanks for the papers, David. The first one is a g...   Oct 20 2005, 22:13
||||- - duff   QUOTE (Pio2001 @ Oct 20 2005, 07:48 PM)QUOTE ...   Oct 20 2005, 22:52
||||- - stephanV   QUOTE (duff @ Oct 20 2005, 11:52 PM)It's ...   Oct 20 2005, 23:11
|||||- - duff   QUOTE Might be... or might be not. You can't c...   Oct 20 2005, 23:36
|||||- - KikeG   QUOTE (duff @ Oct 20 2005, 11:36 PM)I think i...   Oct 21 2005, 00:00
||||||- - rjamorim   QUOTE (KikeG @ Oct 20 2005, 09:00 PM)Also, ps...   Oct 21 2005, 00:15
||||||- - duff   QUOTE (KikeG @ Oct 20 2005, 11:00 PM)QUOTE (d...   Oct 21 2005, 00:29
||||||- - rjamorim   QUOTE (duff @ Oct 20 2005, 09:29 PM)I'm n...   Oct 21 2005, 01:03
||||||- - Mike Giacomelli   QUOTE (duff @ Oct 20 2005, 04:29 PM)The audit...   Oct 21 2005, 05:56
||||||- - KikeG   QUOTE (duff @ Oct 21 2005, 12:29 AM)From the ...   Oct 21 2005, 08:10
|||||- - stephanV   QUOTE (duff @ Oct 21 2005, 12:36 AM)I think i...   Oct 21 2005, 08:34
|||||- - Woodinville   QUOTE (stephanV @ Oct 20 2005, 11:34 PM)Sorry...   Oct 21 2005, 21:19
||||- - krabapple   QUOTE (duff @ Oct 20 2005, 04:52 PM)QUOTE (Pi...   Oct 21 2005, 05:25
||||- - antz   QUOTE (duff @ Oct 20 2005, 10:52 PM)QUOTE (Pi...   Oct 21 2005, 13:39
||||- - Woodinville   QUOTE (antz @ Oct 21 2005, 04:39 AM)Seems to ...   Oct 21 2005, 21:20
|||- - stephanV   QUOTE (bryant @ Oct 20 2005, 07:11 PM)It turn...   Oct 20 2005, 21:43
||- - Donunus   QUOTE (stephanV @ Oct 20 2005, 03:48 PM)QUOTE...   Oct 21 2005, 04:10
||- - stephanV   QUOTE (Donunus @ Oct 21 2005, 05:10 AM)I do n...   Oct 21 2005, 08:43
||- - user   I recall, we have had successful abx tests even he...   Oct 21 2005, 09:20
||- - Pio2001   QUOTE (user @ Oct 21 2005, 10:20 AM)I recall,...   Oct 21 2005, 12:18
|||- - ff123   QUOTE (Pio2001 @ Oct 21 2005, 03:18 AM)QUOTE ...   Oct 21 2005, 17:43
||- - krabapple   QUOTE (user @ Oct 21 2005, 03:20 AM)I recall,...   Oct 21 2005, 21:54
|- - Cartoon   QUOTE (Donunus @ Oct 20 2005, 02:51 AM)I do h...   Nov 12 2005, 13:40
- - KikeG   The "goosebump", emotional factor can be...   Oct 19 2005, 11:54
|- - Donunus   QUOTE (KikeG @ Oct 19 2005, 06:54 PM)The ...   Oct 19 2005, 12:06
|- - kjoonlee   QUOTE (Donunus @ Oct 19 2005, 08:06 PM)actual...   Oct 19 2005, 18:31
||- - Woodinville   QUOTE (kjoonlee @ Oct 19 2005, 09:31 AM)QUOTE...   Oct 21 2005, 01:27
||- - duff   QUOTE If you consider that we are wired to detect ...   Oct 21 2005, 01:38
||- - Woodinville   QUOTE (duff @ Oct 20 2005, 04:38 PM)So we are...   Oct 21 2005, 21:15
||- - duff   QUOTE (Woodinville @ Oct 21 2005, 08:15 PM)QU...   Oct 21 2005, 23:43
||- - Woodinville   QUOTE (duff @ Oct 21 2005, 02:43 PM)When I sa...   Oct 22 2005, 08:00
|- - Lyx   QUOTE (Donunus @ Oct 19 2005, 01:06 PM)QUOTE ...   Oct 20 2005, 06:07
|- - Donunus   QUOTE (Lyx @ Oct 20 2005, 01:07 PM)QUOTE (Don...   Oct 20 2005, 16:51
|- - Lyx   QUOTE (Donunus @ Oct 20 2005, 05:51 PM)QUOTE ...   Oct 20 2005, 21:10
- - KikeG   Well, I think expectation effects in listening tes...   Oct 19 2005, 19:33
|- - krabapple   QUOTE (KikeG @ Oct 19 2005, 10:33 AM)Well, I ...   Oct 19 2005, 20:12
- - krabapple   QUOTE (mirrorsawlljk @ Oct 18 2005, 06:03 PM)...   Oct 19 2005, 20:06
- - Halcyon   There is nothing inherently bad about double blind...   Oct 19 2005, 20:29
- - ff123   Tests that try to distinguish very small effects *...   Oct 19 2005, 20:53
|- - krabapple   QUOTE (ff123 @ Oct 19 2005, 11:53 AM)Tests th...   Oct 19 2005, 23:40
|- - ff123   QUOTE (krabapple @ Oct 19 2005, 02:40 PM)Inte...   Oct 20 2005, 05:38
- - fcmts   There is another problem similar to wine blind tes...   Oct 19 2005, 22:15
- - stephanV   I don't see how that is a problem. The goal of...   Oct 19 2005, 22:22
- - duff   One distinction relevant to this issue is the diff...   Oct 20 2005, 23:00
- - duff   QUOTE The opposite of "blind", I suppose...   Oct 21 2005, 01:27
- - Jun-Dai   I think it's pretty clear that double-blind te...   Oct 21 2005, 07:22
- - KikeG   For helping doing long-term, casual listening-like...   Oct 21 2005, 08:30
- - duff   QUOTE Seems to be a lack of understanding of somet...   Oct 21 2005, 16:48
|- - stephanV   QUOTE (duff @ Oct 21 2005, 05:48 PM)The reaso...   Oct 21 2005, 17:29
||- - duff   QUOTE (stephanV @ Oct 21 2005, 04:29 PM)QUOTE...   Oct 21 2005, 20:06
||- - stephanV   QUOTE (duff @ Oct 21 2005, 09:06 PM)QUOTE Wh...   Oct 21 2005, 20:21
||- - bryant   QUOTE (stephanV @ Oct 21 2005, 11:21 AM)QUOTE...   Oct 21 2005, 22:53
||- - rjamorim   QUOTE (bryant @ Oct 21 2005, 07:53 PM)But I d...   Oct 21 2005, 23:12
||- - stephanV   QUOTE (bryant @ Oct 21 2005, 11:53 PM)So, if ...   Oct 22 2005, 00:00
||- - ChiGung   QUOTE (bryant @ Oct 21 2005, 10:53 PM)What...   Oct 22 2005, 00:25
|||- - bryant   QUOTE (ChiGung @ Oct 21 2005, 03:25 PM)I have...   Oct 22 2005, 23:39
|||- - ChiGung   just thinking -i do get all sorts of weird sensati...   Oct 23 2005, 00:34
||- - Woodinville   QUOTE (bryant @ Oct 21 2005, 01:53 PM)So, if ...   Oct 22 2005, 07:52
||- - bryant   QUOTE (Woodinville @ Oct 21 2005, 10:52 PM)QU...   Oct 22 2005, 23:32
||- - Woodinville   QUOTE (bryant @ Oct 22 2005, 02:32 PM)The onl...   Oct 24 2005, 21:51
|- - Lyx   QUOTE (duff @ Oct 21 2005, 05:48 PM)QUOTE See...   Oct 21 2005, 17:35
|- - krabapple   QUOTE (duff @ Oct 21 2005, 10:48 AM)QUOTE See...   Oct 21 2005, 22:01
- - duff   QUOTE It sounds counterintuitive that my brain wou...   Oct 22 2005, 00:30
|- - ChiGung   QUOTE (duff @ Oct 22 2005, 12:30 AM)Frankly, ...   Oct 22 2005, 00:47
||- - duff   QUOTE (ChiGung @ Oct 21 2005, 11:47 PM)QUOTE ...   Oct 22 2005, 01:14
||- - ChiGung   QUOTE (duff @ Oct 22 2005, 01:14 AM)The reduc...   Oct 22 2005, 01:26
|- - Woodinville   QUOTE (duff @ Oct 21 2005, 03:30 PM)Filtering...   Oct 22 2005, 08:07
- - ChiGung   A simplistic example - a sine wave of exactly 3122...   Oct 22 2005, 00:59
|- - Woodinville   QUOTE (ChiGung @ Oct 21 2005, 03:59 PM)A simp...   Oct 22 2005, 08:08
|- - ChiGung   QUOTE (Woodinville @ Oct 22 2005, 08:08 AM)QU...   Oct 22 2005, 14:09
- - ChiGung   -Sorry for flooding a bit there. Tasty subject   Oct 22 2005, 01:01
- - duff   So sorry for the long delay. I didn't forget a...   Nov 10 2005, 20:10
|- - Woodinville   QUOTE (duff @ Nov 10 2005, 11:10 AM)Woodinsid...   Nov 10 2005, 20:23
- - duff   I don't understand why you would want to maint...   Nov 11 2005, 00:41
|- - Woodinville   QUOTE (duff @ Nov 10 2005, 03:41 PM)Somehow, ...   Nov 11 2005, 21:52
|- - Pio2001   QUOTE (duff @ Nov 11 2005, 01:41 AM)The ABX p...   Nov 12 2005, 03:00
|- - Woodinville   QUOTE (Pio2001 @ Nov 11 2005, 06:00 PM)I can ...   Nov 12 2005, 09:33
|- - user   There aren't theoretical flaws with abx or DB ...   Nov 12 2005, 10:52
- - KikeG   Sorry, you still have provided no evidence that wh...   Nov 11 2005, 14:34
|- - Woodinville   QUOTE (KikeG @ Nov 11 2005, 05:34 AM)Sorry, y...   Nov 11 2005, 21:56
|- - Pio2001   QUOTE (Woodinville @ Nov 11 2005, 10:56 PM)Su...   Nov 12 2005, 02:32
- - duff   Let's back up a moment... There are at least ...   Nov 11 2005, 18:37
- - KikeG   About the first point, your degraded examples are ...   Nov 11 2005, 19:57
- - duff   QUOTE Well, if it's inaudible, there's a g...   Nov 11 2005, 21:19
- - Woodinville   QUOTE (duff @ Nov 11 2005, 12:19 PM)In other ...   Nov 11 2005, 21:59
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