Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.1 (Tek) 9/26/83; site azure.UUCP
Path: utzoo!watmath!clyde!akgua!sdcsvax!bmcg!cepu!trwrba!trwrb!sdcrdcf!hplabs!tektronix!teklds!azure!toddv
From: toddv@azure.UUCP
Newsgroups: net.audio
Subject: ERRE: Equalizers
Message-ID: <2748@azure.UUCP>
Date: Thu, 3-May-84 10:39:41 EDT
Article-I.D.: azure.2748
Posted: Thu May  3 10:39:41 1984
Date-Received: Tue, 8-May-84 00:04:23 EDT
Organization: Tektronix, Beaverton OR
Lines: 38

> What do equalizers do?

Your system and speakers produce a frequency band of sound that isn't 
necessarily flat.  That is, different frequencies will be produced with 
differing efficiency.  The room that your speakers are in (where the 
speakers are placed, what kind of furniture and how it is arranged, the shape
of the room, carpeting, drapes, etc) have perhaps the greatest effect in
determining what your system will sound like.

A graphic equalizer is designed to compensate for this.
The trick is knowing how to set the controls.  Because I don't have any test
equipment easily available to me, I bought an equalizer that generated pink
noise (noise that is equally modulated at all frequencies) and contained
a graphic analyzer.  When the equalizer generates the pink noise, it is
passed through the amp and heard over the speakers.   A calibrated microphone
plugs into the graphic analyzer portion of the equalizer, and is placed in the
room at a desired listening location.  Each channel is adjusted separately
to produce (as closely as possible) a flat response from 20hz to 16khz.
Note that the equalizer only works for one point in a room at a time
(although other points may also work out accidently, but I doubt it.)

I also use the pink noise to determine which tape works best on my system.
I record pink noise on a tape, and play it back while observing the display 
of the graphic analyzer.  Some tapes clip the high end much more than others.

Without a pink noise generator, and a graphic analyzer I don't think an
equalizer is anything more than a toy.  However, some people use them to adjust 
the sound to taste (irrespective of the response curve).

I *think* I have an Audiosource EQ-1.   Nothing to brag about, but I leave that
to the tyros.  I'm sure you can find a similarly cheap equalizer.  On the
other hand, if you want to spend BIG bucks, someone is sure to accommodate you.

                 Todd Vierheller

PS.  I'm not a REAL audiophile.  (I buy and enjoy MHS records.)