Wisdom Audio Series SCS - Manual (Page 11)

11
Surround Speakers Surround channel geometry
In a 5.x channel system, the surround should be placed either directly to the
sides of or slightly behind the listening area (90°–110° from the center channel,
as seen from above). In a 7.x system, the surround speakers should be closer to
90° from the center speaker, and the surround back speakers should be at ap-
proximately 135°–150° from the center speaker. This conforms to industry stan-
dards, and ensures that you hear what was intended from a spatial placement
point of view. (Too often, the surround speakers are all behind the listeners, cre-
ating a big “hole” in the soundfield between the front and the back.)
L R
C
Sub 1
Sub 2
L
s
R
s
R
b
L
b
22°
30°
90°
110°
135°
150°
0°
a 7.2 channel system layout
One possible exception to these guidelines: if you have a THX ® -certified pro-
cessor and are using the THX Advanced Speaker Array™ circuitry, you should
follow the guidelines in your owner’s manual for the processor. Using this
technology, it can actually be more effective to have the rear speakers in a 7.x
system directly behind you and immediately adjacent to each other.
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 usually
centered on each of the four walls, or deep in the corners of the room. If you
have the luxury of doing so, this simple placement strategy can reduce the size
of the room’s response irregularities from 20 decibels down to perhaps as little
as 6-8 decibels—a tremendous improvement.