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Blind tests discussion

Paul Dormer media at clara.net
Wed Dec 9 17:29:38 EST 1998

In the area of high end sound replay, there are varying opinions on
whether some audio equipment can actually produce audible effects.
This includes some CD players, cables and amplifiers.

The scientific angle is that if a component measures transparently
beyond the range of audibility, using known techniques (eg FR within
0.1db 20Hz-20Khz / >96db S/N ratio etc) then this equipment is doing
nothing sonically.

A small number of double blind trails have added weight to this
argument, suggesting that what is perceived as an audible difference
between two components is effectively a demonstration of the placebo
effect... yet many listeners remain unconvinced.

It seems to me that the double blind test is flawed, especially in
circumstances where the thresholds of audibility are challenged since
there is no way of making objective measurements which can confirm
ultimate sensitivity.  A psychological factor could come into play
which masks our ability to perceive very fine detail under such
conditions.  The scientific evidence seems to be open to speculation.

I'm interested in the views of audiologists here on double blind
testing, psychological factors, and "thresholds of audibility."

Perhaps there is some physical indicators which correlate with
thresholds as demonstrated in tests, maybe there is still room for
speculation on an ability to hear (or feel?) beyond 20Khz or to low
levels of distortion and noise.

Can you confidently specify what the thresholds are?

Do you have ultimate faith in the results of double blind trails?

Paul Dormer      Media at clara.net
Sound Design, Editing, Mastering

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