PowerBass 3XL Series, Manual

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• BANDPASS ENCLOSURE: The most common bandpass enclosure is a combination of a sealed and a
vented enclosure working together (4th order or single reflex bandpass system). The rear of the speaker
goes into the sealed chamber while the front of the speaker goes into the vented chamber. Because the
vent produces all the sound generated from this type of enclosure, sound quality may not be as good as
a well-designed ported or sealed design. Often the sacrifice for sound quality and subwoofer cone control
is greater SPL output. However unlike a sealed or vented enclosure, you can effectively increase the
enclosure sensitivity with the appropriate tuning choices. You can choose to design a narrow frequency
band with very high sensitivity or choose a wide frequency band with the sacrifice of lower sensitivity. The
damping effect of the vented chamber reduces the motion of the cone so that potentially higher sound
output is achieved without the subwoofer reaching its mechanical limits. Minor deviations from design
recommendations however may result in frequency response and distortion problems.
(If you are intending to use multiple subwoofers in your system, PowerBass recommends having
separate chambers for each subwoofer if the subwoofers will be operated by two different amplified
signals. This will prevent any possible cancellation.)
NOTE:
Due to the vented backplate, you must allow an additional 2" behind the subwoofer when
designing your speaker enclosure.
CAUTION:
If the air volume of the speaker enclosure is larger then the recommended size or used alone
in a free air application will cause serious damage. It will not only deteriorate in durability, but eventually stop
functioning.
ENCLOSURE VOLUME
To calculate the volume required for your enclosure please refer to the Recommended Enclosures section
of this guide for your specific model number. These are listed in both cubic feet and liters. One cubic foot is
expressed as 12" x 12" x 12" = 1728 cubic inches (see picture below).
12" x 12" x 12" = 1728
3
Inches"
12”
12”
12”
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