[net.audio] More on flat EQ's

gwes@inmet.UUCP (05/16/84)

#N:inmet:2600078:000:683
inmet!gwes    May 14 10:31:00 1984

(line eater)
Equalizers which are set at zero can influence sound quality.  Even
good ones - though the effects are more subtle.

1) More stages - ANY gain stage gives some distortion.

2) Unequal summing - that is, instead of a flat response, the equalizer
gives an "average" flat response when set at zero.

3) Resonant effects - this includes frequency sensitive delay.
This one gets worse as the number of bands increases because the Q
(sharpness of resonance) gets higher for narrower bands.  That causes
more time delay.

Note that this can still affect the "flat" response.  See any "all pass"
delay equalizing filter.

	Geoff Steckel (cca!ima!inmet!gwes or harpo!inmet!gwes)