wjm@whuxk.UUCP (08/24/83)
In defense of Equalizers - Like any other active device, an EQ will, theoretically
introduce some (albeit very small in a good design) noise. The question is
Is the minute amount of additional noise added by a good EQ box worth this
price (as well as its effect on one's wallet)?
I contend that the answer is yes, since a good EQ properly used can
1) compensate for nonlinearities in speakers or room acoustics
By being able to use less expensive speakers one can pay for an EQ box this way
although I don't like the idea philosophically. However, many highly regarded
home and car speaker designs use the concept of using EQ to cancel out known
irregularities in the speaker response to get an overall flat response - The
Bose 901 is probably the best known speaker using this principle in the home
and the GM/Bose car system also uses it with excellent results.
2) let you "correct" (I put the term in quotes since it is a matter of personal
opinion) recordings which you feel were mixed incorrectly.
3) enhance the overall response of your system - an equalizer allows you to
do the same thing one does with tone controls but with a much finer range
of applications.
Personally, I don't think any stereo system costing over $1.5K should be
without an equalizer, in order to guarantee that you're getting full value for
the bucks you paid for it.
As for myself, I generally set the controls on my EQ (an Audio-Control C-101)
to equalize my speakers (which, frankly, are not as good as the rest of my
system and will be replaced when I get some more bread) and then leave it alone.
I'm from the so called "New England" school of ruler-flat response and use
the EQ box to level out some peaks in the speaker response (the speakers have
a peak around 7KHz or so and tend to have a weak high end).
As for recommendations, EQ's come in several varieties but I strongly recommend
getting one with a built-in spectrum analyzer and calibrated microphone (unless
you have access to these things from other sources) since it is quite difficult
(and a royal hassle) to adjust an EQ to fix up speaker and room response by ear
when using a test record (the Telarc Omnidisk has the necessary pink noise bands
to do this).
The two main types of EQ's are the graphic (which have separate sliders for
each frequency band - usually 10, one for each octave) and the parametric
(where you not only adjust the gain of the filter but can also adjust the
center frequency and its width). Parametrics are much more flexible but are
harder to adjust (and cost more) so unless you have a particularly nasty room
response abberation a 10 band graphic unit is the way to go. (If you need
a parametric, SAE makes a nice one).
Among the 10 band graphics, my favorite (not just because I own one) is the
Audio Control C-101, which has a built in spectrum analyzer. It is also
very convenient to use since the left and right channel sliders for each
band are next to each other (which is nice, since the bass tends to be set
the same in both channels). Other units that I've heard good things about
are the Soundcraftsmen and the dbx 20/20 (although you pay through the nose
for dbx's computerized adjustment feature which does room adjustment automatically
The signal/noise and distortion figures on any of these units is in the same
range as good electronics (less than .01% distortion and S/N of 100-120 dB or
so in most case) so I wouldn't bee too concerned about adding much noise.
Happy EQ!
Bill Mitchell
Bell Laboratories - Whippany NJ
the usual disclaimer-these are my personal opinions and are not necessarily
those of my employer, Bell Laboratories