Wisdom Audio Wisdom & Sage Series SC-1 - Manual (Page 22)

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are all behind the listeners, creating a big “hole” in the soundfield
between the front and the back.)
a 7.2 channel system layout
Subwoofer Placement Subwoofers offer somewhat greater flexibility in placement, since the frequen-
cies they reproduce are not readily localizable by the human ear. This is due to
the fact that the wavelengths they reproduce are more than ten feet (3 meters)
long, but our ears are located only about 6-7 inches (≈ 17 cm) apart. Thus these
extremely long waves do not contribute meaningfully to the imaging that the
main speakers create.
However, this fact does not mean that the placement of the subwoofers has no
effect on the sound quality in the room. Far from it. The subwoofers are the
most likely to suffer from the response irregularities introduced by the room
itself, operating as they do below approximately 80 Hz in most systems.
Recent research into the behavior of rooms as a function of speaker placement
has concluded that — if you have the freedom to do so — there are significant
advantages to placing several smaller subwoofers around the room, rather than
relying on a single large woofer. Moreover, the optimum placement is usu-
ally centered on each of the four walls. If you have the luxury of doing so, this
simple placement strategy can reduce the size of the room’s response irregulari-
ties from 20 decibels down to perhaps as little as 6-8 decibels.
Reducing the room’s inherent problems to this degree is a huge advantage. It
allows the SC-1 to put its considerable abilities to work on perfecting your sys-
tem’s response, rather than on trying to perform major corrective surgery.
Room Treatment Rectangular rooms have six reflecting surfaces (four walls, ceiling and floor)
that reflect sound to the listener, after various delays introduced by the indirect
routes the sound waves take on their way to the listener. These first reflec-
tions are particularly damaging to sound quality. Looking at the simplest case
of stereo reproduction, you have a minimum of twelve first reflection points in
your room that deserve some attention.
Unfortunately, it is often difficult to do much about the ceiling and floor reflec-
tions, even though they are arguably the most destructive. (The minimization of
these reflections is one of the strongest arguments for the tall, line source loud-
speakers that Wisdom Audio builds.) This leaves you with eight “first reflections”
that you should consider minimizing somehow. These points are easily found by
having a friend move a small mirror along the four walls of the room, while you
sit at the listening position. Any place on the wall where you can see a reflec-