The MDS amplifier features a built-in combination variable high and low pass crossover.
The low pass filter works together with the (subsonic) high pass filter to achieve band
pass filtering. This concentrates the amplifier’s output power to your woofer’s optimum
frequency range for maximum performance.
Before making adjustments, lower the (subsonic) “High Pass” control to 10Hz by rotating
in the full counter clockwise position. Next select the desired Low Pass frequency. The
crossover point should be determined by the speaker’s recommended operating range.
Once you have set the “Low Pass frequency, adjust the “High Pass” control clockwise
while listening to the system until you hear the Bass output start getting thinner (lower) in
sound then stop. This will filter out the subsonic frequencies below the speaker’s normal
operating range for improved output.
Fine tune the bass by adjusting the Bass Boost Control to deliver up to 12dB of boost at
45Hz.
You can add up to 12dB bass boost by
increasing the Bass Boost control.
Filter out unwanted subsonic frequencies
below the woofer’s audible range by
adjusting the high pass filter.
Select the Low Pass crossover point
for your woofers.
A
DJUSTING THE X-OVER AND BASS
Fine tune the amplifier's input sensitivity.
T h e g a i n s e n s i t i v i t y c o n t r o l f o r t h e M D S
amplifier is located on the side panel. This gain control
has been included to allow adjustment to properly
match the output of the radio. This is one of the most
misunderstood adjustments. By rotating the control in
the clockwise direction, the amplifier‘s input will
become more sensitive and the music will play louder. This
is not a volume control and you will not get more power out of the amplifier in the
maximum position! It may seem to deliver more output, but actually the system is only
playing louder faster as you turn the volume control on the radio. Ideally, to properly level
match the system the goal is to achieve maximum output from the amplifier without
distortion at about 3/4 of the volume control.
To determine if the amplifier’s gain is set properly, turn the system on and slowly increase
the volume control. You should be able to use about 3/4 volume before the system gets
loud but not distorting. It is very important when making these adjustments that you do
not over drive the speakers (at point of distortion) this will cause permanent damage to
the speakers. If you are unable to achieve 3/4 volume before distortion you will need to
adjust gain control (in this case you would reduce the gain). The gain controls should be
adjusted very slowly. It may help to have another person to assist you by adjusting the
gain controls while you listen for distortion.
F
INE TUNE THE SYSTEM
11
MAX
MIN
LEVEL
0.2V
5V
BASS BOOST
12dB
OdB
HIGH PASS
LOW PASS
50Hz
400Hz
10Hz
40Hz
