[net.audio] equalizers as a means for overcoming loudspeaker deficiencies

jeff@tesla.UUCP (Jeff Frey) (08/11/83)

There have been suggestions that a multi-band equalizer would do the same
as a mid/high replacement for improving mid/high performance.  BUt if a
tweeter drops off sharply at, say 16kHz, wouldn`t a lot of boost above
that just increase distortion--or at least, increase distortion while
increasing output?

My receiver has a mid-range tone control which I use, in addition to
Bass & Treble controls, to produce what I think is realistic sound.
To apoint, the mid-range control is OK but after only a couple of dB
of boost, the effect becomes very UNrealistic (probably due to the
broad frequency range affected by the control, or the contour over the
range).  Boosting the treble, however, produces nasty sound with even
a little boost.  Wouldn`T the really fundamental way to improve
loudspeaker response be to build the best loudspeakers anyway?

I know there are electronic dynamic-feedback loudspeaker systems, and
systems that have their electronics carefully tailored to overcome
measured speaker deficiencies (the BBC has at least one monitor system
like that) but in these cases the whole thing is done from a systems
approach.

I`ve always felt that multi-band equalizers, sold to "improve room response"<
were yet another gimmick (although they probably could work to eliminate
unfortunate resonances and dead spots for exactly one place in a room);
to overcome loudspeaker response problems---?
Jeff

michaelk@tekmdp.UUCP (Michael Kersenbrock) (08/13/83)

How can you tell if it is your loudspeakers or your room that is deficient?
Don't they work as a system?  Do you audition speakers in an anechoic 
chamber? If you do, is your living room one? Is there meaning to life?
(oops, got carried away).  These are the standard questions that still
seem to be unanswered adequetely despite much discussions one way or
the other.
  I've looked at my speakers (AR9s) with a "real time analyzer" before
and after my having moved them to an ajacent wall from their previous
position.  The difference is substantial -- with the same speakers.
  Equalizers can be useful particularly for very moderate cost speaker systems.
In higher end systems they become less useful (relatively), but can
still be of good use. In my system, equalizing for a flat response (AFTER
having moved the speakers mentioned above, my living room is small) according
to the 10-band RTA, the equalizer is putting in about a 3db peak-to-peak
correction (most knobs are on "flat", with a few pushed up a tad).
I have found that this modest equalization makes it *sound better*, and
slightly *improves* imaging (although that surprized me a bit). It does
increase the S/N, but at normal listening levels (which is pretty loud, the
amps are >200 w/ch) the noise is inaudible, even playing a CD disk. The
improvement potential of the equalizer will probably not diminish further
until I can replace the house (ha!) that it is in. 
(The equalizer uses Sig. 5532 op amps, and operates at relatively high 
level signals at the preamp OUTPUT.)  For my system, the equalizer may not 
have been cost efficient, but never the less was a useful device. I like
the flashing (up and down) lights too.
   I might point out that almost everyone has a graphic equalizer on their
system, although most of them are only two band devices ... labeled "bass"
and "treble" . . .

Mike Kersenbrock
Tektronix Microcomputer Development Products
Aloha, Oregon