[Joe Bloggs]

I think it's quite possible that some differences cannot be detected in a DBT but are still audible in more relaxed circumstances...

Just because you can't detect the difference in a in a stressful DBT doesn't mean you can't detect the difference all the time. As you pointed out a lot of our cognition goes at the subliminal level. We may not be able to detect a difference when we consciously try to look for it in a short test--nevertheless it's entirely possible that our subconscious can pick out the difference...

And not being able to see what you're listening to or even having your eyes covered may already be disconcerting enough to lower your discriminatory powers a long way...

Having said that, in a non-blind test in a noisy environment, I haven't been able to convince myself that my discman sounded different from a Sony SCD-555ES SACD player. Now if I can take that as final proof that the two are performing on the same level, I can save myself a lot of money

And y'know, people perform very differently in DBT and ABX... do you go to r3mix.net or hydrogenaudio.org? Have you ever seen some published results of blind tests on different formats? There would be a few that can pick out all the different encoders and assign different scores for all of them (and sensible ones--like 5/5 for MPC and 1/5 for WMA and not the other way around...) while some can only pick out a few, and most gave 5/5 and never get listed in the results because this has no informational value.

To put it bluntly, if you can't tell the difference in a blind test, you may just have tin ears, or you may just be no good working in a blind test. (like me actually

)

 

[Ricky]

Quote:

Originally posted by Joe Bloggs Just because you can't detect the difference in a in a stressful DBT doesn't mean you can't detect the difference all the time. As you pointed out a lot of our cognition goes at the subliminal level. We may not be able to detect a difference when we consciously try to look for it in a short test--nevertheless it's entirely possible that our subconscious can pick out the difference...

Well, the test doesn't have to be short or stressful. It may be stressful but only because you're not used to them, are afraid of the result, etc. But as long as it is double-blind and level matched, you can do the test at any way you desire.

Quote:

And y'know, people perform very differently in DBT and ABX... do you go to r3mix.net or hydrogenaudio.org? Have you ever seen some published results of blind tests on different formats? There would be a few that can pick out all the different encoders and assign different scores for all of them (and sensible ones--like 5/5 for MPC and 1/5 for WMA and not the other way around...) while some can only pick out a few, and most gave 5/5 and never get listed in the results because this has no informational value.

Yeah, I visit those sites very often, and have seen those results. (I'm KikeG at there).

Well, the main point in DBT tests is first to detect if there is a difference, just and only that. If you detect a difference, then and only then after that, you can rate or describe the difference if you want. And about identifying all the encoders, well, that is far above of what I'm talking here.

As I'm sure you know, in these forums only ABX tests (one type of double blind tests) are accepted as proof of transparency or non-transparency of encoders.

 

[Joe Bloggs]

*sigh*

The problem is, ABX / DBT may be like the 95% significance test in statistics--if it can't pass the test, there is still a good chance that the two are in fact different--it's just that you couldn't pick it out in your limited test.

In the case of DBT in audio the problem is how to get the listener to perform at the same performance during the test as during his/her casual listening. Limited length and duration of sonic memory, difference in the environment from his / her normal listening environment, difference in psychological state, etc. all affect the end result.

And at the end of the day, just because you can't pick out one from the other in a DBT doesn't mean you can't enjoy one more than the other when you're not doing DBT. *sigh*

 

[Leporello]

It is possible that there are differences between cables that cannot be detected in a blind test, but only in so-called sighted tests. What we need is evidence to support this claim. Possibility is not enough.

It is also possible that a switch-box obscures the differences between cables. What we need is evidence to support this claim. Possibility is not enough.

It is also possible that there are differences that cannot be measured, at least not yet. What we need is evidence to support this claim. Possibility is not enough.

The burden of proof is on those making the claims.

If we think our blind test was limited (for example too short) it is time to run that test again. If it was not valid in some other way, it is time to design a better test.

Science is not only about making up interesting hypotheses (important as that may be). It is also about backing those hypotheses with evidence. There will be no proof in the absolute sense of the word. It is all about statistics and probabilities.

If even discussing ‘DBT’ is to be prohibited on this forum, we might just as well add ‘evidence’ on the list of forbidden words. To speak of open mind…

Regards,

L.

 

[Hirsch]

Quote:

Originally posted by Ricky But for your little experiment to be valid from a scientific point of view, has to be double-blind, sorry. That's how drugs efectiveness is tested, because that is the only reliable method.

Actually, this is only partially true. DBT is not used in drug testing where there might be adverse effects to withholding a particular treatment. It is also not used when there are side effects to a particular compound that make it impossible to disguise. Somehow, we come up with reasonably reliable methods of detecting efficacy anyway.

Quote:

Bias is a BIG distortion factor when comes to detect differences in sound. Humans are prone to overdetect differences in sound. Bias has effect even at non-conscious subliminal levels, so even if you believe you are not biased, bias is something you simply can't control, as we are humans and not machines. I have had the experience. Some things I thought sounded very different, suddenly sounded very similar if not equal in some cases, when confronted with a properly done blind test. Why not just try it for yourselves? Afraid of doing it? Where's your curiosity? Who's mind closed?

The one thing that I can absolutely, positively guarantee is that if you have used DBT on yourself to convince yourself of the presence or absence of anything, you have not done a properly designed DBT. You have simply determined that you can't hear a difference in that situation, which by no means implies that there is no difference. If I do a DB visual perception test on my father, I can demonstrate that blue is perceived the same as green (He's color blind). If you use DBT on yourself, and have not detected a difference, have you proved anything beyond your own inability to perceive? Have you even proven that?

The first thing you need, before you go any further in conducting a DBT, is a sample of the population of interest of appropriate size. If you've actually done a DBT properly, how have you conducted your sample size calculations?

Jude, my apologies for the response to the troll.

 

[Leporello]

Hirsch,

Please correct me if there is something wrong with my reasoning: we need appropriate-sized population samples only if we want to make generalizations "into" that population (sorry about my English...)

However, for a given individual it would be sufficient if he/she scored in a blind test in a statistically significant way repeatedly.

This would be evidence enough, that this particular individual is able to differentiate between cables. So far, I have never seen anybody provide this kind of evidence.

Regards,

L.

 

[Hirsch]

Statistics is for the most part about populations. Take a single individual, and give that person 1000 trials. Assume that person gets the right answer 510 times. Any mathematical analysis you attempt will tell you that this falls within the realm of chance. The person cannot tell a difference...

Now take 1000 people, and have them all score between, say 505 and 515 out of 1000. You'll get a very powerful statistically significant effect indicating that as a group, this sample is scoring higher than chance. They can tell a difference, despite the large number of mistakes made.

Now, can that original person who scored 510 out of 1000 actually tell the difference? Who knows? Probably not even the person himself. You have to run an appropriately sized experiment to tell you what that score means.

 

[Anders]

I am a little reluctant to throw me into this discussion on DBT (double blind test). However, I think that I have a point that has not be expressed yet. I will begin with my conclusion:

The only DBT that may be useful for an audiophile is the one you do on yourself!!!

If you can accept the following, reasonable assumptions (I will not prove them), you will understand why.

1. Results will depend on the choice of cables. With some sets of cables, very few or noone will hear any difference at all. With other sets many more will hear a difference.
2. Results will depend on the selection of test subjects. Some subjects will repeatedly hear the difference, some most of the time while others never will surpass the statistical probability of guessing.
3. There is a phenomenon called experimentation bias, meaning that the result of a DBT can be screwed by differences between an artifical experimental situation and real-life situations. I don't say it would be impossible, but I have never felt deep engagement in music when A-B-ing.

With regard to differences in 1 - 3, you can get great variation in the results of DBTs.
Let's assume that you find a DBT that convincingly shows that there is a difference between Radio Shack bulk, Kimber PBJ and Cardas Neutral Reference. This means that there is a statistical difference between the ratings of these cables for a group of listeners.
But you still don't know anyting about these essential questions:
A. Do I belong to the group of persons who can hear differences between cables?
B. If I can hear differences, would my priority be the same as the group mean?
C. If I have the same priority and Cardas is put on top, is it worth the price difference?
D. Should I only choose between the cables that are tested in DBT?

The conclusion is: If you think that DBT is necessary: OK, but the only meaningful way is to do it on yourself.

A second conclusion it that Jude made a wise decision when banning DBT discussions.

Finally, I will shortly explain why cable DBTs are pseudo-scientific. DBT is a scientific method but something does not become science by just using the method. DBTs of a lot of cables may, if properly conducted, accumulate knowledge, but a very specific knowledge. A common demand in science is that the experiments are connected to theoretical formulations or at least are generalisable. The state of knowledge in this area seems to be far from this stage. I don't know if these physical, physiological and psychological processes are too complex. This is probably one reason, another can be that there are other areas of research that are regarded as more essential for purely scientific reasons or practical purposes. At least one thing is clear, noone will get even a buck of research funding just for throwing in some cables in a DBT.

 

[MusicJunkie]

I have a really stupid question....

What is DBT??

 

[Anders]

Recently I noticed this acronym on the forums listning without understanding it until I read the "about cables" thread. It is double blind test, mostly used in medical research on pharmaceutics, where it is the most appropiate procedure.
I have added this to my previous post for readers who haven't read the whole thread.

 

[Satori]

While by no means is it acurrate(but it makes me happy), I've gone to several shops that have a nice couch setup in a listening room and have had one of the employees switch pieces of equipment without me watching and the results are pretty good. No I'm not talking about cables, but with other components. It does seem to be the best way to determine what to spend your money on.

I mean to be honest can you trust any of the reviews around? To many people have a bias based on the brand names. Look at all the Team whatevers around here. And once you get over $50 or so an interconnect the differences become smaller and I would guess preconceived ideas win out.

Just my thoughts.

 

[Hirsch]

This time I really am going to honor the rules and be silent. My apologies once again for failing to do so earlier.

 

[Anders]

Hirsch, this was not an argument with you. I don't mean that one can do the DBT alone, at least two assistants are needed!
Some of the thinking was inspired by you, but the formulation was not precise enough.

 

[cyclingasronomer]

i am honestly trying to figure out why some people keep telling us we don't hear a difference. are they really trying to convince us that what we hear, we don't? or are they trying to tell others not to listen to us, and not to listen to their own ears? it seems to me, that if one doesn't believe that anyone can hear a difference, he would decide to go to another site and talk to others who don't want to believe those of us who do, and who don't want to listen for themselves. i don't mean this to be a sarcastic jab, just an honest thought. why not just encourage them to listen. if one doesn't hear, he doesn't. why bring science and philosophy into a defence of wanting to remain ignorant of what one could hear if he tried. i don't mean ignorant as an insult, just the state of not knowing what one might hear if one listened. this is a site for listeners. why are we arguing about theory instead of discussing what we hear? philosophy and science are fun and interesting, but this is not the purpose of this site. or maybe i'm wrong. i guess i should take the advice of the last writer and shut up!

 

[kwkarth]

Quote:

Originally posted by Ricky Well, the test doesn't have to be short or stressful. It may be stressful but only because you're not used to them, are afraid of the result, etc. But as long as it is double-blind and level matched, you can do the test at any way you desire. Yeah, I visit those sites very often, and have seen those results. (I'm KikeG at there). Well, the main point in DBT tests is first to detect if there is a difference, just and only that. If you detect a difference, then and only then after that, you can rate or describe the difference if you want. And about identifying all the encoders, well, that is far above of what I'm talking here. As I'm sure you know, in these forums only ABX tests (one type of double blind tests) are accepted as proof of transparency or non-transparency of encoders.

Ricky,
It would be virtually impossible to set up an uncompromised DBT with these cables, unless you had a complete uninitiated, non-hi-fi person conduct the test. The cables themselves are very different looking physically to the point that it would be impossible to disguise them, and further, it would be impossible to introduce a switching mechanism that in and of itself would not further degrade the sound and obfuscate differences. If you could achieve a true DBT without compromise, I would be most interested in participating.