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AMPLIFIERS
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The following list of terms with their definitions is offered
as help in understanding the set-up and operation of
your amplifier.
1. Crossover (xover) - an electrical filter with high-pass
or low-pass characteristics that divides the frequency
range into playable bands for certain speakers.
Subwoofers, mid-bass, midrange and tweeters are all
designed to play different frequencies and should do so
to avoid damage. The xover point is where the playable
frequencies cross from one speaker to the next at -3dB
below reference level.
2. Full-range - refers to signals which cover the entire
audio frequency span from 20Hz to 20kHz.
3. High-pass - simply put, this blocks lower frequencies
which damage smaller speakers, and passes the higher
frequencies for smaller speakers like the midrange and
tweeter.
4. Low-pass - you got it, this is the inverse of a
high-pass. It blocks higher frequencies and passes
the playable lower frequencies to the larger speak-
ers, like subwoofers.
5. Impedance - the resistance to the flow of current in an
alternating current circuit (such as with music). Line
level circuits are typically a high impedance of several
thousand ohms, while speaker level circuits are usually
a low impedance of a few ohms.
6. Line level - the type of signal produced at the outputs
of tape decks, CD tuners, preamplifiers, etc., with a
typical value of a volt or less in a high impedance circuit.
7. Speaker level - the type of output that is meant to
drive speakers. These signals are sometimes called
high level and are usually connected by two conductor
speaker wires.
8. Signal - the signal of an audio system is what is heard
from the speakers. These signals may be high pass, low
pass or full-range.
We don’t have enough space for Electronics 101, so if
you have a good, bad or amusing question, please call us
TOLL FREE at 800-CALL MTX! (800-225-5689)
Adjusting the Gain
1. Turn the gain controls on the amplifier all the way down.
2. Turn up the volume control on the source unit to approx-
imately 3/4 of maximum.
3. Adjust the front channel gain control on the amplifier
until audible distortion occurs.
4. Adjust the front channel gain control down until audible
distortion disappears.
5. Follow steps 3-4 for rear channel and sub-channel gain
settings.
6. The amplifier is now calibrated to the source unit’s out-
put. The rear and sub channels may be adjusted accord-
ing to your personal taste.
Typical Speaker
Wiring
Configurations
Definitions of Common Terms
+ + - - +
- L L R R
s
u
b
OK
Two 4 ohm speakers for
sub channel
One 4 ohm speaker for
bridged stereo channel
4 ohm
4 ohm
+ + - - +
- L L R R
s
u
b
OK
Four 8 ohm speakers for
sub channel
Two 8 ohm speakers for
bridged stereo channel
8 ohm
8 ohm
4 ohm
8 ohm
8 ohm
8 ohm
8 ohm
+ + - - +
- L L R R
s
u
b
NOT
OK
Three or more 4 ohm speakers
for sub channel
Two 4 ohm speakers for bridged
stereo channel
4 ohm
4 ohm
4 ohm
4 ohm
4 ohm
Note: The information shown for
bridged stereo channels is good
for both the front and rear channels
5-Channel Amplifier
Mono Amp and Bridged Stereo Amp
Impedance Requirements
— 2 ohm minimum for sub (mono) channel
— 4 ohm bridge minimum for stereo channels
— 2 ohm stereo minimum for stereo channels
Read this if you wanna be a do-it-yourselfer
–
or give us a call at 800-CALL MTX.
Problem Cause Solution
No LED indication No +12V at remote connection Supply +12V to terminal
No +12V at Power connection Supply +12V to terminal
Insufficient ground connection Verify ground connection
Blown power fuse Replace fuse
LED on, no output Volume on head unit off Increase volume on head unit
Speaker connections not made Make speaker connections
Signal processing units off Apply power to signal processor
All speakers blown Replace speakers
Output distorted Head unit volume set too high Lower head unit volume
Amplifier gain set too high Lower amplifier gain
Balance reversed Speakers wired L + R reversed Wire speakers with correct orientation
RCA inputs reversed Reverse RCA inputs
Some balance reversed Some Speakers wired L + R Wire speakers with correct orientation
reversed
Some RCA inputs reversed Reverse appropriate RCA inputs
Bass is boomy Thunder EQ too high Lower setting
Bass is weak Thunder EQ too low Raise setting
Speakers wired out Wire with correct phase
of phase
Not using MTX woofers Buy MTX woofers
Blowing fuses Excessive output levels Lower volume
Amplifier defective Return for service
Troubleshooting