Kenwood AMPED XR-S17P Training Manual page 30

For power hungry people (you know who you are), the KAC-9104D offers
a Dual Mono Drive connection that allows you to strap two KAC-9104D
amps together to power a single subwoofer—that's 1800 Watts of power!
Combine this with a Kenwood sub and your system could be banned in
several counties. Don't say we didn't warn you!
Imagine the installation opportunities
of a crushingly powerful Class D amp
that's just over 13 inches by 9 inches!
Dual Mono Drive on the KCA-9104D means
you can use up to two KAC-9104D per
subwoofer and double the power to an
earth-shaking 1800 Watts RMS!
Boost Your Bass
We've added bass boost circuitry on all new compact size amps. Acousti-
cally speaking, low frequency sound (bass) is harder to hear than high
frequency sound, and you have to tweak it to get the most out of low range
sound. By amplifying a specific frequency range, bass boost results in
well-balanced sound and better sound from the bass and bass drum.
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Inaudible Frequency, You Are Cut Off!
The KAC-9104D and KAC-8104D (and all 2008 eXcelon amps) have a
built-in infrasonic filter that helps subwoofers perform their best by sharp-
ly cutting off inaudible frequencies below 15 or 25 Hz (depending on
amplifier model). Although this will improve the sound of subs in sealed
enclosures, the biggest audible benefit is for subs in vented boxes. A
subwoofer in a vented enclosure acts like a free-air subwoofer below
the tuned frequency of the box. At these infrasonic frequencies, the air
in the box offers no resistance to the movement of the woofer cone, so
the only thing keeping the woofer in-line are its suspension and spider.
This dramatically increases distortion and reduces the woofer's power
handling, sometimes resulting in blown woofers. By eliminating the inau-
dible junk, the infrasonic filter improves the woofer's control, improves its
sound quality, increases its power handling, and saves amplifier energy
for the music that we can hear.
The infrasonic filter reduces distortion
by filtering out super low frequencies
that subwoofers can't reproduce.