Architect
Model 110-Model 210-Model 210ES
Installer’s Guide
™
Introduction to
Equalizers and
Acoustics
13
A Short Introduction to
Equalizers and Acoustics
Magazine reviewers and audio system owners spend much
time critically appraising speaker and other stereo compo-
nents. 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
speakers. Like waves in a pond created by a splash, sound
waves emanate from the transducers (drivers) in your speak-
ers 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, rein-
forcing and canceling each
other as shown in the figure
above. Since sound is energy,
the way it reflects depends
upon the angle of the sur-
face, the type of material and
the frequency of the sound
wave. Because your listen-
ing 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 fre
-
quencies of sound have different wave-lengths (a function of
frequency and the speed of sound). Each frequency’s wave-
length 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
Room interaction
