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  1. #1
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    Two questions about DBT.

    You know, the kind that the cable skeptics always write about.
    1. When the DBT is being administered - by qualified people - is the system and room being used in the test, known or unknown to the test subjects?
    2. Is the music being used, during the testing, also known or unknown to the test subjects?

    Just curious.
    Remember, different isn't always better, but it is different.
    Keep things as simple as possible, but not too simple.
    Let your ears decide for you!

  2. #2
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    Generally they would not be told anything. Is the selection important? Very much so. Cable advocates, at least those you might take seriously if you were inclined to consider their arguements, claim that only high resolution sound systems can reveal the differences between one cable and another. Therefore, to prove whether or not the cable differences are audible you would want to start with equipment that would give the best chance for giving a positive result. They could also easily and credibly argue that some music is much more likely to reveal these differences than others. Perhaps music with great dynamic or frequency range. And of course, you want to select the candidates most likely to hear a difference, those with excellent hearing and experienced listeners. In other words, a real and objective study to discover true knowledge does not mean sitting a few people in a room, trying out a few cables and not telling anyone which are which, and then tabulating to see if the results are statistically significant.

    What would a professionally run study consist of? First of all, a DBT would be devised to find the most sensitive situation where there is the best chance of getting a positive result. The best available equipment, the most demanding music, the best listeners. If they cannot tell the difference, nobody else would be expected to either. If they can, then it has to be determined what changes in the test would give a negative result. Lesser equipment, less demanding music, people with poorer hearing or without any ear training or listening experience.

    Suppose the results revealed that only 15 % of the population could hear a difference, and only when listening to certain kinds of classical music, only on sound systems whose performance makes them cost $10,000 or more, and then only if they listen intensely. Then it would be stupid for 99% of the people who own audio systems to buy them. On the other hand, if it turned out that 85% of the population could hear a difference, that it is audible with any type of music and on any sound sytem costing over $1000, and that even casual listeners could hear a difference, then anyone should consider buying them. We do not have this knowledge today because those with a vested interest in selling this product have no desire or need to find it out. All it could potentially do is reduce their sales and profits. There are enough customers who so worried about being wrong that they are ready to part with their money on unproven products, especially when someone else tells them to, even without any demonstrable evidence of their value.

  3. #3
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    You didn't answer my questions.
    Let me clarify my first question. Is the systems and rooms that of the test subjects, or are they completely different, i.e. foriegn to the test subjects. Different equipment, different room size and acoustics? A completly different listening enviroment?
    Remember, different isn't always better, but it is different.
    Keep things as simple as possible, but not too simple.
    Let your ears decide for you!

  4. #4
    Music Junkie E-Stat's Avatar
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    Quote Originally Posted by skeptic
    Is the selection important? Very much so.
    Amen. Zapped by Jitter would assert the only untrained folks listening to completely unfamiliar material should be used for expediency.


    Quote Originally Posted by skeptic
    Cable advocates, at least those you might take seriously if you were inclined to consider their arguements, claim that only high resolution sound systems can reveal the differences between one cable and another. Therefore, to prove whether or not the cable differences are audible you would want to start with equipment that would give the best chance for giving a positive result. They could also easily and credibly argue that some music is much more likely to reveal these differences than others.
    Yes, keep going.


    Quote Originally Posted by skeptic
    What would a professionally run study consist of? First of all, a DBT would be devised to find the most sensitive situation where there is the best chance of getting a positive result. The best available equipment, the most demanding music, the best listeners. If they cannot tell the difference, nobody else would be expected to either.
    I wonder why then that is never the case? I have yet to see a single test of any sort using that criteria that supports the "all wire sounds the same" assertion. Mtrycraft gave me a nice list, but none of the references that I could readily look up met that criteria and gave null results. The only one that did from Tag McLaren merely concluded that their $300 /meter IC sounded no different than a $300 / meter Nordost IC. I think that Mtry really didn't fully read the report as he obviously didn't with the supposed "Russell findings" given that Russell conducted no tests himself.


    Quote Originally Posted by skeptic
    Suppose the results revealed that only 15 % of the population could hear a difference, and only when listening to certain kinds of classical music, only on sound systems whose performance makes them cost $10,000 or more, and then only if they listen intensely.Then it would be stupid for 99% of the people who own audio systems to buy them.
    That is an entirely rational business conclusion for those who peddle gear to the mass market. It makes total sense from an overall marketing standpoint.

    It does not, however, deny the fact that many folks can hear qualitative differences using better cables on better systems.

    rw

  5. #5
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    Simple. No one is interested in speniding the money on a known outcome of a null. Senseless.
    The oines published have been with the doubting Thomasas who dare to show up on testing day. Many back out and chicken out of fear.
    Why don't you set one up? After all, you seem to be making all sorts of claims for audibility, yet not a single cited reference to support any of the claims. Oh, references thaz stand up.
    mtrycrafts

  6. #6
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    Quote Originally Posted by bturk667
    You know, the kind that the cable skeptics always write about.
    1. When the DBT is being administered - by qualified people - is the system and room being used in the test, known or unknown to the test subjects?
    2. Is the music being used, during the testing, also known or unknown to the test subjects?

    Just curious.
    Most DBT studies I have seen don't give much background information, so I'm not sure about the answers to your questions. However, I would assume in group tests, not all subjects in the group would know the test room like they know their own listening room at home. As for the music in the test, some subjects probably would know it better than others, and it might be new to some.

  7. #7
    Forum Regular FLZapped's Avatar
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    Quote Originally Posted by E-Stat
    Amen. Zapped by Jitter would assert the only untrained folks listening to completely unfamiliar material should be used for expediency.


    rw
    You're misquoting. Only with the correct testing set-up to match. Yes it is expediant when you are doing multiple tests per day on multiple products, one needs a better mouse trap or nothing would ever get done.

    -Bruce

  8. #8
    Music Junkie E-Stat's Avatar
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    Quote Originally Posted by FLZapped
    You're misquoting.
    Don't think so.

    "While we're at it, I suppose you also think that it is okay for the participant to be familiar with the test material, that it won't introduce another bias..... "

    http://java.audioasylum.com/cgi/m.pl...offee&session=

    "All the tests I've participated in did not require training."

    http://java.audioasylum.com/cgi/m.pl...offee&session=

    Here is a summary of other pearls of wisdom regarding your notion of DBTs gleaned from other posts:

    http://java.audioasylum.com/cgi/m.pl...at&r=&session=

    rw

  9. #9
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    My view

    Quote Originally Posted by bturk667
    You know, the kind that the cable skeptics always write about.
    1. When the DBT is being administered - by qualified people - is the system and room being used in the test, known or unknown to the test subjects?
    2. Is the music being used, during the testing, also known or unknown to the test subjects?

    Just curious.
    I haven't read the responses of others so excuse any duplication. In my experience most blind testing would be done on unfamiliar systems in unfamiliar listening rooms. There are, however, reports of individuals being tested on their own equipment, in their own listening rooms, with music chosen by the subject as being the most "revealing" segments of their own collection. The people at home also can take as long as they want to listen and almost always confirm that they hear differences prior to the test.

    Of course, when tested. they consistently fail to demonstrate that they can hear differences between cables or even electronics. Some very subtle factors ARE reqularly indentified in DBTs including subtle volume differences.

    I did note that skeptic quotes highenders as referring to "high resolution" systems. The phrase only has meaning in terms of measureable quantitities: distortion and frequency response accuracy. Most reasonable systems (not including speakers) have trivial (non-audible) differences in these factors. Differences in the quality of the recordings consistently exceed any measurable differences in reasonable quality audio systems. High resolution is a mythical buzz word as used by the high end except in regard to speakers where significant differences in frequency response into a given room do exist.
    Last edited by RobotCzar; 02-03-2004 at 09:03 AM.

  10. #10
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    "High resolution is a mythical buzz word as used by the high end except in regard to speakers where significant differences in frequency response into a given room do exist."

    I'm not going to debate whether or not one amplifier sounds different from another. However, the term high resolution like mid fi is a perjorative term which some snobish and frankly not well educated audiophiles use to distinguish the most expensive equipment from mass marketed equipment. What they don't know is that not only is their boutique manufactured onesy twosy equipment grossly overpriced because of huge markups and inefficient manufacturing methods, but that much of it doesn't even perform as well as some of the mass market products at a fraction of the price. What is high end or high resolution depends on who you talk to. One audiophile's high end product it another's overrated piece of junk. But objectively, much of is is old or even antiquated design sometimes carried through to rediculous extremes. But then again, some people will buy just about anything so why shouldn't someone steal their money. If they don't, someone else surely will.

  11. #11
    Forum Regular FLZapped's Avatar
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    None of the stuff you quoted has anything to do with your original statement, beyond the statement of fact in what I have participated in.

    Nice try, but you're still misquoting.

    -Bruce

  12. #12
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    Quote Originally Posted by FLZapped
    None of the stuff you quoted has anything to do with your original statement, beyond the statement of fact in what I have participated in.
    Sure it does. Here's my analysis of the original question, Skeptic's reply and your previously stated comments on that topic:

    Question:

    2. Is the music being used, during the testing, also known or unknown to the test subjects?

    Skeptic's reply:

    Generally they would not be told anything. Is the selection important? Very much so.

    Your response concerning "the selection of music" being known to the participant:

    I suppose you also think that it is okay for the participant to be familiar with the test material, that it won't introduce another bias.....

    I observed that you believe that the listener should not know the selection under test. I added your related comment concerning the use of an untrained listener.

    rw
    Last edited by E-Stat; 02-03-2004 at 09:05 PM.

  13. #13
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    It depends on the claim maker. If the claim maker says he can tell the difference 100% of the time between cable z and cable y in any system then by all means test him. A basic blind test will prove that claim wrong. And heck we even let him fail a few times and we'll still call him a success.

    Or is the claimant saying that "I can hear a difference some ofthe time on some recordings and thus I would spend the exta money on cables." If it's the latter your test just got a whole lot more complicated. Why because the human brain will ALWAYS make a selection between X and Y in a test. It has been proven over and over that if you play the identical piece of music from the identical system and you tell the subject there are two cables when there really is only one...our brain being a decision maker will make a decision. The questioning is of course leading in these circumstances but it shows how bad our brains want to solve problems when in fact there is no problem. Your brain does the same thing visually when you stare at a blob of clouds. It invents an image from your past experience. You've seen 300 goats when you grew up and so 20 years later you're staring at a bunch ofblobby clouds and surprise you see a Goat. You would bever see the goat in the clouds if you never had the opicture in your brain to start with. And in audio when you EXPECT there to be a difference even when there is none you will hear one.

    To your question. You have to be well versed in listening to both items under test. Cable abc and cable XYC you should have lots of hours of listening to both...and presuming you're fairly sure hat when level matched they sound different. YOU choose the recording you feel will show up the best in a test...listening experience is of course important both with the whatever the material you're testing is and of course the music...since after all Validity would mean you'd be playing stuff you know because that is in fact what you'd be playing in your normal living space.

    The room should be kept the same for the claim...thus if you claimn ABC sounds better than XYZ and you made that claim based off of YOUR system in YOUR chair in YOUR room with YOUR music then that is where the test has to be located. Unless you're claiming others will notice it in their rooms...after all most can't know that because even speakers don't sound the same in different rooms.

    You listen to the identical piece of music in both systems not the first 20 seconds of song A on ABC wire and 1:20 to 1:40 of song B on XYZ wire. I have seen and laughed at so many of these such tests - and even the mighty AES doesn't clue into it. If EVERYTHING is not exactly the same you can't know what you're testing.

    The best service the down and dirty DBT can do is stop certain audiophiles making egregious claims that there is a Night And day difference between X and Y cable. If that's the case the more expensive one is deliberately screwing up the sound. It's not hard to deliberately make a speaker wire sound different...the very fact that people are not hearing the difference ttells more about how bad the testsare than the products. It is in the companies BEST INTERESTS to deliberately make their gear sound different - sounding good or better is another matter.

    Any scientific test that is written and cannot be completely reproduced - IE; all information is provided with all specifics then take those and wrap it around the toilet role because that's what they're worth.

    Medical science and nutrition shows with glaring results that HIGH reliability without the proper validity makes something SEEM to be the case turn out to be completely wrong. As a starting point that red meat makes you fat and is bad for you. trials into the 200,000 range came to that conclusion. But oops all the people eating the red meat were also eating bread, rice and potatos and the scientists blamed the Red Meat for the ills. Now that researchers after 30 years clued in -= starting with less than a dozen of the thousands of experts decided to test the Red Meat WITHOUT all the Carbohydrates. No heart problems, no fat gain, not a damn thing wrong with it. The Carbs on the flip side have caused an explosion of obesity and diabetes. Thanks to those dozens ofscientists getting Duke and Harvard medical to stop guesing and making assumptions based off high reliabilty. High Reliability is extremely dangerous without valididty. It just racks up supporting statistical correlation which impresses statistically. If one single variable is skewed like it was above, then all these scientists wasted all those years testing something completely wrongheaded at the outset.

    BTW, people put to much faith in the brain. There is a saying that humans only use 10 % of our brain - it's totally untrue. Psychologists KNOW for a fact that we use 100% of our brain...Psychologists only lnow what 10-15% it actually does. WHich leaves a big fat 85-90% variable smack dab in the middle. And since any testing environment....ANY TESTING ENVIRONMENT I say again is not the SAME as the normal listening environment then you have nother big variable. Do with all that as you may.

    That doesn't mean we should go around believing every cockeyed claim...but I can't disprove it with a problematic test...I can however have doubts. Which means I can save money.

    I kinda wish the anti-cable guru's would go after the drug companies. Now there is a group selling innefectual piece of crap and often HARMFUL products that need some fighting. And their mark-ups make cable salesman look like chumps in the profit margin departments.

  14. #14
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    Quote Originally Posted by okiemax
    Most DBT studies I have seen don't give much background information, so I'm not sure about the answers to your questions. However, I would assume in group tests, not all subjects in the group would know the test room like they know their own listening room at home. As for the music in the test, some subjects probably would know it better than others, and it might be new to some.
    Actuall they do. Most are in subjects home or at his audio store where he is so intimately familiar with the stuff. Most use their own music. There is no restriction on any of the two asked question. None of it has made a difference.
    It is hard to get 'golden ears' to keep their promises to participate, to be home when promised.
    mtrycrafts

  15. #15
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    Quote Originally Posted by mtrycraft
    It is hard to get 'golden ears' to keep their promises to participate, to be home when promised.
    That's what I like - a man who never makes claims for which he does not have sound empirical data to support.

  16. #16
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    Quote Originally Posted by pctower
    That's what I like - a man who never makes claims for which he does not have sound empirical data to support.
    Yep, you only have to ask the right person for all the good audio stories about golden ears promised DBT demontsrations just to be skipped out on you. Doesn't take too many.
    mtrycrafts

  17. #17
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    I wonder if there has been any analysis of the effect of the stress of being tested has on one's hearing, or ability to distinguish sonic differences?

    During any of the DBT's oft refered to, are measurements taken of testee's heart rate, andrenalin levels etc. I tend to find that I hear far more from my system when I am relaxed than when I am stressed.

  18. #18
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    Quote Originally Posted by maxg
    I wonder if there has been any analysis of the effect of the stress of being tested has on one's hearing, or ability to distinguish sonic differences?

    During any of the DBT's oft refered to, are measurements taken of testee's heart rate, andrenalin levels etc. I tend to find that I hear far more from my system when I am relaxed than when I am stressed.
    From what I know there may have been a lot of work in this area, but much of it seems proprietary and not particularly oriented to high end audio. More having to do with compression methods and that type of stuff. And, unfortunately when two people who possess that propretary information begin disagreeing with one another they are limited in what they can reveal, so they often just end up yelling at one another.

    One of the unfortunate things about this whole debate is that the real experts that should be chiming in - the people with psychology or other similar non-EE backgrounds - don't participate. Just because someone has an engineering degree doesn't mean he knows beans about proper DBT protocol. It's even worse when you're a lawyer like I am.

  19. #19
    Forum Regular FLZapped's Avatar
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    Quote Originally Posted by E-Stat
    Your response concerning "the selection of music" being known to the participant:

    I suppose you also think that it is okay for the participant to be familiar with the test material, that it won't introduce another bias.....

    I observed that you believe that the listener should not know the selection under test. I added your related comment concerning the use of an untrained listener.

    rw
    That was not my reply in this thread and not related to his original misquotation. -Bruce

  20. #20
    Forum Regular Monstrous Mike's Avatar
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    Here is good article which has discussion on the ability of listeners in audio evaluation:

    http://www.harmanaudio.com/all_about...rt_science.pdf
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