[Arny Krueger]

http://en.wikipedia.org/wiki/High_fidelity

Ascertaining high fidelity: double-blind tests
Double-blind testing has been required in the approval of new medicines
since about 1960. Although single-blind testing of loudspeakers had been
used for a number of years by Floyd E. Toole at the National Research
Council of Canada, the double-blind audio listening test of amplifiers was
first described in the United States by Daniel J. Shanefield in November of
1974 in the newsletter of the Boston Audio Society. This was later reported
to the general public in High Fidelity magazine, March 1980. The
double-blind listening comparison is now a standard procedure with almost
all audio professionals respected in their field. For marketing purposes, a
few manufacturers of very expensive audio equipment dispute the need for
this test. A commonly-used improvement of this test is the ABX-listening
comparison. This involves comparing two known audio sources (A and B) with
either one of these when it has been randomly selected (X). The test and its
associated equipment was developed by the Southeastern Michigan Woofer and
Tweeter Marching Society (SMWTMS)--a semi-professional organization in
Detroit that is very active in the double-blind testing of new audio
components. An alternative view is that such testing is stressful, and
perhaps because of this, is unable to distinguish the fine subtleties of top
equipment; that only long-term listening will allow one to get to grips with
its true sound -- furthermore that proponents of double-blind testing have
an agenda to discredit that such subtle differences exist, that they are
purely self-delusionary and victims of advertising hype. However, there is
still another level of argument that maintains that all serious listening
comparisons can be stressful. Also, listeners who paid an unusually large
price for playback equipment might have a subconscious tendency to favor it.
Therefore most professional audio testing uses double-blind comparisons.