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From: rcd@opus.UUCP (Dick Dunn)
Newsgroups: net.audio
Subject: Re: Equalizers and Hearing Deficiencies
Message-ID: <458@opus.UUCP>
Date: Tue, 15-May-84 02:32:03 EDT
Article-I.D.: opus.458
Posted: Tue May 15 02:32:03 1984
Date-Received: Sun, 13-May-84 00:35:19 EDT
References: <6927@umcp-cs.UUCP>
Organization: NBI, Boulder
Lines: 29

<>
	On equalizers:
>...I   suspect
>that many people have hearing that deviates several db from  being  flat over
>20-20,000Hz.  Thus, when the analyzer indicates a flat response, you may  not
>be HEARING a flat response...

True enough - in fact, only a rather abnormal human would have flat
response over the audio spectrum.  HOWEVER, what you really want to
equalize is the system up TO (but not including) your hearing.  If you have
nonlinearities in your hearing, your brain compensates for them when you
hear live music - so if the sound system is adjusted to produce the "same"
frequency spectrum as live music, it will sound live to you since the same
sort of sound is arriving at your ear, and your brain will perform the same
compensation.

There's another factor to consider, however--even though your ear has
nonlinear response, it's not the same at different levels.  For example,
you perceive a 60 dB SPL sound at 1000 Hz as being louder than a 60 dB
sound at 100 Hz, by a certain amount (due to nonlinearity; your ear is more
sensitive to the 1000 Hz).  However, you don't perceive the same difference
in level between 100 Hz and 1000 Hz sound at 90 dB SPL.  This means that if
you listen to a live performance and then listen to a recording of that
live performance, reproduced PERFECTLY except at a different overall level,
it will sound "off" in frequency response.  Of course, you can correct this
with EQ also, if you want to.
-- 
...Nothing left to do but smile, smile, smile.		Dick Dunn
{hao,ucbvax,allegra}!nbires!rcd				(303) 444-5710 x3086