Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!linus!wivax!decvax!yale-com!leichter
From: leichter@yale-com.UUCP
Newsgroups: net.audio
Subject: Re: hearing.high.treble
Message-ID: <1701@yale-com.UUCP>
Date: Sat, 2-Jul-83 09:24:53 EDT
Article-I.D.: yale-com.1701
Posted: Sat Jul  2 09:24:53 1983
Date-Received: Sun, 3-Jul-83 01:06:57 EDT
References: whuxk.227
Lines: 27

Most of what you say about hearing the high end is true, but I have to dis-
agree with one statement:  Separation above 16KHz is important because the
sound there is so directional.  While it is true that the SOUND is highly
directional, what matters is whether your HEARING is directional; and, in
fact, it isn't.  Human direction location is best in the midrange.  It fades
out in effectiveness at both ends, even under ideal circumstances.  (There
are several different mechanisms that the brain uses simultaneously, inclu-
ding at least phase differences, gross timing differences, and the shadowing
effect of the head.  At very high frequencies - certainly at 16KHz - the
only one left that works is the shadowing system; in the mid-range, several
contribute and overall system performance is much better.)  In addition,
"ideal circumstances" are unlikely.  16KHz tones will bounce off everything
in your listening room very effectively, and further you'll get standing
waves all over.  Turning your head slightly, or moving it a small amount,
can produce large changes in volume.  The directional information just isn't
there to be found easily, even by a better system.  (I can remember trying to
find the bad power supply in a room full of systems when its Sonalert went off
(a more or less pure tone up around 16KHz or so).  You could hear the damn
thing loudly everywhere in the room - but even standing in front of the bad
unit, you couldn't tell that it was the source.  The only way we were sure
we had found the right one was the feeling of relief at the silence when
we turned it off.)

Anyway...While separation at 16KHz wouldn't be a negative, I doubt you would
hear the difference between, say, 12db and 20db.
							-- Jerry
				decvax!yale-comix!leichter leichter@yale