WILSON AUDIO Alexandria X-2 Series, Руководство пользователя

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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 , I N C .
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LAP
E
CHO
Probably the most obnoxious form of reflection is called “slap echo.” With slap echo, primarily midrange
and high frequency sounds reflect off of two parallel hard surfaces. The sound literally reverberates back and forth
until it is finally dissipated 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:
ƒ It adds harshness to the upper midrange and treble by storing time-domain smearing energy.
ƒ It destroys the delicate phase relationships, which help to establish an accurate sound stage.
Slap echo 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 practical) 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 than can be used to ameliorate slap echo:
ƒ Sonex®
ƒ Airduct board
ƒ Cork panels
ƒ Large ceiling to floor drapes
ƒ Carpeting to wall surfaces
In many domestic listening environments, heavy stuffed furnishings reduce slap echo somewhat. Unfortu-
nately, their effectiveness is not predictable. Diffusers 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 characteris-
tic of the room by making it sound “deader,” less “bright and alive,” and “quieter.” Soundtrack effects will be more
localized. However, over-damping the room can render reproduced sound which is lacking in musical involvement
and “aliveness.”
Diffusers, on the other hand, do not affect the tonal balance characteristic of the room as much. Placed
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