Tech Talk: Sound Dispersion - Egnater VENGEANCE Owner's Manual

Tech talk tips: SOUND DISPERSION
Ever wonder why your 4x12 cabinet sounds better when
you stand off to the side? Did you consider why the pros
mic a speaker from the edge instead of in the center?
Ever have people in the audience tell you your guitar
tone is really loud and shrill but it sounds great to you on-
stage? This is a result of the directionality of loudspeakers.
Speakers inherently do not project all frequencies equally.
As the frequency increases, the dispersion decreases.
In non technical terms, this means the higher you play
on your guitar neck, the more directional your sound will
be. By nature, speakers tend to be somewhat non-direc-
tional at lower frequencies. This means you can stand off
to the side of your cabinet and you will hear basically the
same bass and lower mids as your audience is hearing right
in front of your speakers.
On the other hand, and this is where the trouble starts,
higher frequencies tend to "beam" from the speaker. While
you are standing off axis from your cabinet (not directly in
front of it) you are hearing an even balance of lows, mids
and highs and feeling pretty pumped about your awesome
tone. Unfortunately, unbeknownst to you, the listeners di-
rectly in front of your cabinets are being killed by the high
end that is "beaming". FYI, contrary to what one might
deduce, having more speakers in a 2 by 2 arrangement, as
in a 4x12 cabinet compounds the problem and makes the
beaming even worse. Next time you play take a moment
to walk from side to side and squat down in front of your
speakers. You will be amazed at the difference between lis-
tening off axis (to the side) and listening on axis (directly
in front).
Have you ever seen a band in a small place where you
are hearing the stage volume and wonder why the gui-
tars sound so bright? Doesn't that guitar player hear that
obnoxious high end? That knucklehead must be deaf!?!?
More likely he is standing close to his cabinets and all that
high end is just blowing past his/her legs so he/she doesn't
even hear it.
OK..so now I've pointed out how we've all been play-
ing for years believing everyone in the crowd thinks our
tone is as awesome as we think......or is it? Great, so what
can you do about it? The key is to place your speakers so
you are hearing the same thing as everyone else.
If you can get the cabinets far enough behind you, you
probably will pretty much hear everything just fine. If that
is not possible, try placing the cabinets pointing across the
stage sideways instead of forward at the audience. At least
then you will only be killing your other band members
instead of the audience. Chances are you often want to kill
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the drummer or bass player anyway, right? The best thing
you can do is to tilt your cabinets so that they are pointed
at your head. I guarantee you will set your controls way
different from what you normally do.
There are a number of possible options to combat the
beaming problem. A few companies make a solid disc that
you install in front of the speakers to help disperse or at-
tenuate the high end.
These discs have met with some success though they
do introduce some phasing issues. Also, because there is a
solid piece in front of the speaker, if one places a micro-
phone in front of the disc (which happens quite often at
shows), it can sound weird because the disc is altering the
sound into the mic. There are some other smart people at-
tempting to address the problem.
Most involve using some form of foam piece in front
of the speakers. The method we find works best for both
live, and when placing a mic in front of the speakers,
utilizes a sound absorbing 4" x 1" foam disc placed on the
back side of the grill cloth directly in front of the speaker.
The discs are made of an acoustical foam material that at-
tenuates the beaming highs instead of blocking them.
I'm always surprised whenever this subject is dis-
cussed and many guitar players make the statement "I
hate the way my guitar sounds when I stand in front of my
speakers". The answer is not to simply stand off to the side
so it only sounds good to you because everyone else is still
hearing the sound that you hate. Remember why we play
music? It is for others to enjoy.
We should always make a conscious effort to think
about what the audience is hearing, too.
On that happy note...............
Be the one who makes the shovels, not the one who digs
the ditches
- Ed Kreske