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In Reply to: How Does One Prove You Can Hear Different Cables posted by thetubeguy1954 on May 12, 2006 at 08:15:33:
HiA round of quiet applause for actually doing something real !
I have been in several blind tests and would make the following suggestions.
First, the listener (s) have to be isolated from those running the test.
This is necessary because they can unconsciously influence the test.
In one of the earliest examples of this effect, “Hans the counting horse†was thought to be intelligent, until a scientist thought to block the horses view of his master.
Unknown to the master and everyone else, he had been giving Hans body language clues as to the answers.
Ideally, the person switching the cables or gear is unseen in another room.Acoustic memory fades fast switching back and forth should be done VERY rapidly.
To switch back and forth, try a BIG (old) open DPDT knife switch, these were heavy copper and work well. Alternately a relay assembly of low resistance high current relays could be used and remotely controlled. Contacts that are rated to handle say 50 Amps or more would be essentially “lossless†here.
This way, one could put a box at each end (amp and speaker) and then switch instantly from 2 or more cable choices (depending how many relays you put in).If you are testing two things, you also need to break up the order so that one can’t find a rhythm in the choices.
This is why the best tests are really A,B and X (randomly either A or B).The results can be per person or cumulative group but you have to do “enough†to be statistically meaningful.
For example, flipping a coin ten times and getting heads 6 times means nothing but flipping it a million times and getting 600K IS very significant.
Brush up on statistical analysis as it applies to this kind of test. It is easy to do too few tests and have a “6 heads†result, which is not meaningful.In amplifier tests, it was curious that the “civilians†were as good as the golden ears in hearing differences in power amplifiers. With amplifiers it is CRITICAL to have the levels matched exactly or the slightly louder one clearly wins.
Although speakers are all audibly different the winner here is also “the loudest one†which is a famous hifi store sales trick (when they want to move a particularly profitable speaker).
I would pick several different high quality musical passages throughout and nothing else, this gies you the best chance to memorize the sound and hear change if it does.
Do it alone and in a group, once you have it going you will find it useful I think and if done properly, just like a normal auditory hearing test where it is “ears aloneâ€, you can’t fake the results.
Have fun.Tom Danley
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Follow Ups
- Re: How Does One Prove You Can Hear Different Cables - tomservo 09:09:21 05/12/06 (0)