Audio Control Architect 100, Руководство по установке

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Doing the Deed
12
A Short Introduction To
Equalizers And Acoustics
Magazine reviewers and audio system owners spend much
time critically appraising speaker and other stereo components.
Unfortunately, a phenomenon that has a very large effect upon
sound is not is easily judged or changed. That effect is the
ACOUSTICS of the environment in which you are listening.
Room acoustics is a complicated subject about which entire
textbooks have been written. We simply want you to be aware of a
few basics that have a direct effect
on real time audio analysis.
Sounds is waves, as you
probably learned in junior high
school. In a stereo system, these
waves are created by the speak-
ers. Like waves in a pond created
by a splash, sound waves emanate
from the transducers (drivers) in
your speakers and spread out into
the room. If your room were
infinitely big, that’s all there
would be to it. But just as waves
in a pond reach the bank and
reflect back, sound waves bounce
off walls, ceilings, and floors,
reflecting, reinforcing and cancel-
ing each other as shown in the figure above. Since sound is energy,
the way it reflects depends upon the angle of the surface, the type
of material and the frequency of the sound wave. Because your
listening position is likely to be towards the back of the Free Field
waves shown in the diagram, you also get part of the reflected
Reverberant Field as well.
Now we add the next set of complications: Different frequen-
cies of sound have different wave lengths (a function of frequency
and the speed of sound). Each frequency’s wavelength contributes
differently to the Free and Reverberant Fields because they are
different sizes. For example, a 32Hz bass note has a wavelength of
35 FEET, while a 16,000Hz note has a wavelength just under a
tenth of an inch. Tiny treble waves can be caught and neutralized
by draperies, carpeting, upholstered furniture and gangs of indo-
lent Persian cats...while gigantic bass waves simply slosh back and
forth in the room.
Room interaction