Wilson Audio WATT Series 7 - Manual (Page 38)

Non-parallel walls do not support slap echo, but rather allow the sound to diffuse.
Slap echo is a common acoustical problem in the typical domestic listening room, be-
cause most of these rooms have walls of a hard, reflective nature, usually being only oc-
casionally interrupted by curtains or drapes. Slap echo can be controlled entirely by the
application of absorptive materials to hard surfaces, such as:
• Sonex
• Airduct board
• Cork panels
• Large ceiling to floor drapes
• Carpeting to wall surfaces
In many domestic listening environments, heavy stuffed furnishings are the primary
structural control to slap echo. Unfortunately, their effectiveness is not predictable. Dif-
fusers are sometimes also used to very good subjective effect, particularly in quite large
rooms. Sound absorbent materials such as described above will alter the tonal charac-
teristic of the room by making it sound “deader,”much heavier in bass tonal balance,
less “bright and alive” and “quieter.” These changes usually make the room more pleas-
ant for conversation, but sometimes render it too dull in the high frequencies to be mu-
sically involving. Diffusers, on the other hand, tend to not change the high frequency
tonal balance characteristic of the room, but make the sound more “open”. A combina-
tion of absorbtive and diffusive treatments is usually the best approach.
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Another type of reflection phenomenon is “standing waves”. Standing waves
cause the unnatural boosting of certain frequencies, typically in the bass, at certain dis-
creet locations in the room. A room generating severe standing waves will tend to make
a loudspeaker sound one way when placed in one location and entirely different when
placed in another. The effects of standing waves on a loudspeaker’s performance are
primarily, as follows:
• Tonal balance-Bass too heavy
• Low-level detail- Masked by long reveration time LF standing
waves
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