Treatment & Placement - Niles CM8SW Installation & Operation Manual

Treatment & Placement
Typically, sheetrock encloses the sub-
woofer in most installations. Sheetrock has
a fairly loud resonant "twang" compared
to the rigid non-resonant enclosures of
most floor standing subwoofers. None of
the following modifications are absolutely
necessary, however any one or combina-
tion of them will improve the performance
of the subwoofer.
Minimum Enclosure Size
The CM8SW will produce magnificent
results if the ceiling air cavity above the
woofer is a minimum of 1900 cubic inch-
es. If the ceiling joists center measure
5-1/2" deep (2x6) and are spaced 14-1/4"
apart (16" spacing) you would want the
length of the air cavity to be a minimum of
24-1/4" . A larger cavity is fine.
Insulation
Lay a batten of fiberglass insulation (e.g.
R-19 un-batted insulation) on top of the
speaker. If you have more than one sub-
woofer in the room, place the same amount
of insulation above each subwoofer. If your
enclosure is smaller than the recommended
1900 cubic inches, try packing more insula-
tion into the space above the speaker. This
effectively increases the enclosure size.
Enclosure Bracing
Insert small pieces of 1x2 or 1x1 scrap
wood as wedges between the ceiling
sheetrock and the floor above if possible.
Do not use too long of a piece as you
could create a bulge in the ceiling surface.
Enclosure Lining
Purchase some subwoofer damping mate-
rial from a car stereo store (there are vari-
9
ous brands available, e.g. Dynamat
Apply the damping material to the bottom
of the floor above the CM8SW and to the
top of the surrounding sheetrock ceiling
beside the subwoofer.
Speaker Placement Techniques
Although the CM8SW has extensive ability
to compensate for unusual placements with
its crossover switches; placement is still the
primary tool for satisfying your particular
listening needs.
Maximizing Output
Corner Placement – Placing your subwoofer
near a corner will increase the volume of
bass sound produced by the subwoofer!
This is called the boundary effect. Generally,
you can expect a 3dB increase in sound
pressure level with corner placement.
Proximity – Place the subwoofer as close
as possible to the primary listening posi-
tion. Sound dissipates indoors at approxi-
mately 4dB to 6dB each time you double
the distance from the subwoofer to the lis-
tener. Therefore you can expect a 4dB to
6dB increase in output every time you
halve the distance from the subwoofer to
the listener.
Improving the Stereo Image
Near Satellite
Place the subwoofer(s) as close as possible
to the satellite speakers.
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