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Section Nine: Suggestions for Optimal Use of the GRAPHI-Q
Like any powerful tool, the GRAPHI-Q offers an infinite number of possible control configurations, and
the choices may at times appear overwhelming. Here are some helpful considerations for maximizing
the audio quality of your sound system, by taking advantage of the many powerful features of your
GRAPHI-Q.
9.1. SYSTEM SETUP SUGGESTIONS
Long, long, ago, before the dawn of digital signal processing, sound engineers went bravely forth to their
gigs, armed more with knowledge than with electronics. Fortunately, we now have both knowledge AND
great tools like the GRAPHI-Q, but let’s review some nonelectronic considerations for optimal sound
system setup. (Our apologies to those of you who already know this information...of course you’ve
already quit reading!)
9.1.1. Acoustics.
You may not be able to build a bass trap in a boomy room, or convince a night club owner to carpet the
dance floor. But if you are putting the GRAPHI-Q in a permanent installation, or your own rehearsal or
project studio, there may be some easy-to-implement ideas that will help the acoustics prior to the
introduction of amplification. Here are a few suggestions:
1.
Ideally, a room with nonparallel, non-reflective surfaces that is large enough to accommodate a full
wave length (30 feet+) low bass frequency will provide you with fewer resonance points, a more
evenly balanced room response, and less feedback.
2.
If you’re working in a less-than-ideal acoustical environment (like most of us), you might be able to
do some simple acoustical treatment. Try to break up reflective patterns caused by hard, reflective
surfaces by covering at least one surface with an absorbent material. Duct board (used to make
air conditioning ducts), made of compressed fiberglass, is cheap and works well...but be sure to
cover the exposed fiberglass with fabric or carpet (fiberglass is nasty stuff). If you’re rehearsing on
a cement garage floor, carpeting the floor will help both your feet and your ears (by cutting down
on some of the boomy reflections).
3.
The smaller the room you’re working in, the more the bass problem you’ll have. You might consider
building a bass trap to selectively absorb bass frequencies. Many of the current trade publications
offer advice on easy, inexpensive bass trap construction.
9.1.2. Equipment Placement
If you’re moving your sound system around and can’t rebuild the room each time you move, or if you’re
working in an environment where you’ve done all you can to improve the acoustics, here are a few rules
of thumb that will help your system sound better:
1.
Placement of speakers and microphones. Obviously, avoid when possible pointing microphones
directly at speakers, as this will optimize the likelihood of feedback. For the stage, it’s best if the
house speakers are lined up at the front of the stage, and the microphones are set up further back.
Be aware also that placing speakers close to the floor, wall, ceiling, or especially a corner, will
reinforce the amount of bass energy heard from the speaker (you can alter the bass response of
your system just by speaker placement!). Finally, aiming speakers so that they reflect sound from
a wall or large object back into the microphone should also be avoided.
2.
Microphone considerations. Directional (cardioid) microphones reduce sound coming from behind
and beside them and are less likely to feed back than omnidirectional microphones (which pick up
sound equally from all directions). Stationary microphones are less likely to feedback than mobile
microphones (frequency response will change as a function of location; more locations means more
variety in frequency response, which means more frequencies can feed back). Finally, educating
mic users in proper mic technique will reduce the need to add gain when someone does not speak
or sing in close proximity to the microphone.
3.
Placement of your “mix position.” Ideally, you should set up your mix position out in front of the house
speakers, closer to one set of speakers (not in the middle if you’re sending sound out left and right
speaker stacks), and not too close to a reflective room boundary like a wall. This will assure you
of hearing sound directly from a speaker, uncolored by reflections or phase cancellation arising from
the same sound reaching your ears at two different times.
Section Nine: Suggestions for Optimal Use of the GRAPHI-Q
