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Re: perception of circling horn (was: Doppler Effect Question)



----- Original Message -----
From: "Paul O. Johnson" <pojhome@SWBELL.NET>

Thanx for your comments, John. I thought we localized sound only through
the
slight differences in time of arrival and intensity at the two pinnae. Do
we
know the weighting our brains place on phase differences?


Quite a bit. Try this experiment. Take a stereo, wire the two speakers
correctly (in phase), separate them by about 10 feet, and then play a MONO
source through both speakers (a voice works really well). Stand midway
between the speakers and back about 10 feet. You will easily localize the
sound as coming from between the two speakers. Now reverse the wires on ONE
of the speakers. The sound you now hear will be diffuse and without
particular direction. [This was the phasing test I had on an old setup
record. A voice was recorded on both channels first in phase then out. The
voice described what you should hear. If you heard the opposite, your
speakers were out of phase.]

P.S. The more standard phasing test for speakers (assuming your wires are
not color coded) is to place the two speakers close together, play music
with considerable bass content, then reverse the leads to one speaker. The
wiring with maximum perceived bass is the correct one.

Rick

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Richard W. Tarara
Associate Professor of Physics
Department of Chemistry & Physics
Saint Mary's College
Notre Dame, IN 46556
219-284-4664
rtarara@saintmarys.edu

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