Kenwood AMPED XR-S17P Training Manual page 34

Double Your Bass
When two 4-ohm speakers of the same impedance are connected
in parallel to a single amp channel (both speakers' '+' terminals
are connected directly to the '+' terminal on the amplifier, and the
same for the '–' side), it cuts the impedance in half. Therefore, two
4-ohm woofers become one 2-ohm woofer system, which doubles
the power output of the amp. This also doubles the amount of cone
area producing sound. So instead of doubling the amount of amps
in the car to get more bass, you can just double the number of
subs in the car! (Keep in mind, this same system connected to
a bridged 2-channel amplifier would be unstable as the bridged
amplifier would see a 1-ohm load.)
4-Channel & 2-Channel Amps
If you're working with full-range or component speaker systems, the
KAC-X20 2-channel and KAC-X40 4-channel amplifiers are an excellent
match. The KAC-X40 4-channel amp is 70 Watts x 4 RMS @ 4 ohms with
variable low pass filter, infrasonic filter, selectable phase inverter, K-STAT
technology, and an advanced cooling system. The KAC-X20 2-channel
amp is 180 Watts x 2 RMS @ 4 ohms with variable low pass filter, vari-
able high pass filter, infrasonic filter, phase inverter, K-STAT technology,
and cooling system.
Kenwood 4/3/2-channel amps include the KAC-8404 and KAC-6404. The
KAC-7204, KAC-6202, and KAC-5203 are stereo/bridgeable. Depending
on the number of speakers you want to power, use a 2-channel amp to
power two full range speakers or two subs, with one on each channel.
Otherwise, you can bridge the amp to single channel operation for a
single woofer or woofers (be careful not to drop the impedance below 4
ohms bridged). A 4-channel amp can be bridged to 2-channel mode to
power a pair of subs or full range speakers.
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K-STAT: Better Sound at All Volume Levels
Many amplifiers will have higher distortion when they first power up be-
cause it takes time to reach the optimal operating temperature. K-STAT
(Kenwood Self Tracking Audio Transistor) technology on the KAC-X20
and KAC-X40 multi-channel amplifiers is a Kenwood patented output
transistor that biases automatically based on heat. It does this much
faster than a conventional transistor and offers solid audio benefits. The
biasing circuit, which ensures the amplifier adjusts property, is built into
the device rather than installed separately. This streamlined design re-
sults in lower distortion both when the amp powers up, and at full power.
K-STAT technology also reduces thermal resistance but increases power
for improved sound quality.
eXcelon multi-channel amplifers
KAC-X20 and KAC-X40 have K-STAT
output devices with built-in thermistors
with temperature detection and com-
pensation.
High Pass/Low Pass Crossovers
All Kenwood amplifiers have built in crossover networks that should be
properly set to maximize performance. Not even a Kenwood speaker
can cover the entire range of human hearing, so most speakers are de-
signed to cover sections of that range. Woofers cover low frequencies.
Mid range drivers pick up where the woofers leave off, and the tweeters
take over at the high frequencies. Woofers sound really bad playing mid
range, and mid range drivers distort and bottom out trying to play bass.
Tweeters just burn up if they play anything but the highest frequencies.
Pay attention to electronic crossovers because they filter out frequencies
speakers shouldn't play.
The high-pass crossovers in Kenwood amplifiers cut-off low frequencies
so that the front and rear speakers get only the frequencies that they
were designed to handle. This improves power handling so they can play
louder with more clarity and less distortion.
Low-pass crossovers do basically the same thing—subwoofers are de-
signed to play bass notes. The low-pass crossovers in Kenwood amps
cut off higher frequencies, letting the front and rear speakers do all the
singing while the subwoofer happily thumps out low bass notes.
eXcelon Two-year Warranty
Don't forget to remind customers that eXcelon amplifiers include a two-
year warranty—twice the warranty period of many other manufacturers.