WILSON AUDIO Watch Dog, Owner'S Manual

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W i l s o n A u d i o S p e c i a l t i e s
over time. You can test for slap echo in any room by clapping your hands sharply in
the middle of the room and listening for the characteristic sound of the echo in the
midrange. Slap echo destroys the sound quality of a stereo system in two ways:
• It adds harshness to the upper midrange and treble by storing time-domain
smearing energy.
• It destroys the delicate phase relationships, which help to establish an ac -
curate soundstage.
Slap echo (see Figure 3) is a common acoustical problem in the typical domestic
listening room because most of these rooms have walls with a hard, reflective nature,
only occasionally interrupted by curtains, wall art, or drapes. The best (but least prac-
tical) solution to eliminate slap echo is nonparallel walls. This is because, rather than
support slap-echo, nonparallel walls allow the sound to diffuse. This approach can be
accounted for during the construction process. For existing rooms, slap echo can also
be controlled entirely by the application of absorptive materials to the hard surfaces.
These are absorptive materials that can be used to ameliorate slap echo:
• Illbruck Sonex®
• Air duct board
• Cork panels
• Large ceiling to floor drapes
• Carpeting to wall surfaces
In many domestic listening environments, heavy stuffed furnishings reduce slap
echo somewhat. Unfortunately, their effectiveness is not predictable. Diffusers are
sometimes also used to very good subjective effect, particularly in quite large rooms.