[net.audio] Equalizers and Hearing Deficiencies

prophet@umcp-cs.UUCP (05/06/84)

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One thing that just occurred to me about equalizers:

The equilizer that comes complete with a frequency analyzer may not always be
accurate, because it does not account for hearing deficiencies.   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.  The literature that I have on the Soundcraftsmen
equalizer says that it come with a special test record that you play and  use
to adjust your equalizer.  It claims that using your ear and the record,  you
can adjust the equalizer to give a response that is better than +/- 2db. This
will include any hearing problems that the person may have.

I do not know how well this test record works, since I  haven't  bought   the
equalizer yet, but once I found out I will post to the net if anyone is  in-
terested.

                                Dennis


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ron@brl-vgr.UUCP (05/07/84)

The +/- 2db is probably excellent because I have found that it is
not possible to get finer than about one and a half DB resolution
on most equalizers.

-Ron

seifert@ihuxl.UUCP (D.A. Seifert) (05/09/84)

re: using equalizers to make up for hearing losses

ok, but what does one do when listening to live music?

"high fidelity" is supposed to reproduce the sound of
a live performance, not "improve" it.

If possible, wear hearing protectors when around loud noises.
("a gram of prevention is worth a kilogram of cure")

Of course if you *already* have a serious hearing loss, eq may
be necessary to correct for it.

Of course when you invite your (non-hearing-impaired) friends
over to hear that great new recording you found, the eq will
sound horrible to them.

The obvious solution is a hearing-aid with an equalizer.
They have them for walk-persons, maybe there's hope?
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rcd@opus.UUCP (Dick Dunn) (05/15/84)

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	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.
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