Avalon Acoustics Isis User Manual page 25

Since the floor is within 5 feet of the speaker, it is best to have a carpeted floor
to absorb floor reflections. A thick, dense carpet and pad will absorb lower
frequencies more effectively than a thin one. Due to their complex structure,
carpets and pads of natural materials, such as wool and jute, will exhibit a
more uniform absorption over the frequency spectrum than synthetic
materials will.
It is not necessary to acoustically treat the entire room to achieve good
results. Strategic treatment of specific locations can realize considerable
benefits. Remember that when sound waves reflect from a flat surface, the
angle of reflection is equal to the angle of incidence, just as a mirror reflects
light waves. Therefore, the most important location for sound absorbing
material is the point where the sound waves reflect to the listener (see Figure
8.2).
Figure 8.2 The sound is reflected at the same angle that it struck the
surface; i.e., Angle X = Angle Y. Since light waves obey this same rule,
a mirror can be used to find the point which can be acoustically
damped to avoid early reflections.
Angle X Angle Y
Reflected Sound
Direct Sound
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