SET UP
Placing the x-over switch in the FULL position (MICRO82U/MICRO84U) sets the amplifier to Full Range. This setting allows
ALL frequencies to pass to the speakers. With the MICRO82U/MICRO84U, Placing the switch in the HP or LP position
activates the 12dB crossover, adjustable from 40Hz - 400Hz. . The MICRO81U mono
is dedicated for Low Pass (LP) only with an adjustable frequency from 40Hz - 400Hz.
The MICRO85U (5 channel) amplifier offers full range (FULL) or high pass (HP)
selector switch for channels 1-4. Selecting the high pass (HP) will activate a fixed
70Hz cross over for full range speakers. Channel 5 (on MICRO85U) is dedicated for
subwoofers only but offers an adjustable (LP) crossover from 25Hz – 250Hz.
Placing the switch in the HP position sets the amplifier to the High Pass Filter mode,
enabling frequencies above the cutoff point to pass. Placing the switch in the LP
position sets the amplifier to the Low Pass Filter mode, enabling frequencies below the cutoff point to pass. For system
tuning begin with the frequency set at approximately 80Hz and fine tune up or down based on music choice and input level.
To adjust the gain setting, turn the amplifier gains all the way down (counterclockwise). If using a remote level control
(MICRO81U/MICRO82U), plug the level control into the amplifier and turn it to about "HALF-WAY" (approx. the 12 O'clock
position) this setups the bass boost so you can turn it UP...OR...turn it UP or DOWN when playing different music styles.
Next turn the source unit volume up to almost full volume (usually about 2/3rds of the way up) or until the output starts to
distort on an oscilloscope. This will be NEARLY full volume on some source units, perhaps one or two "clicks" down from
maximum volume. Next, increase the amplifier gain setting until adequate volume is achieved, or until distortion is audible
and then turn it down a bit until the distortion is inaudible.
NOTE: Ideal signal to noise and dynamic range are achieved with the gain at minimum. Most users find adequate gain and
volume is achieved at less than halfway in the adjustment range. Avoid setting the amplifier gain very high as noise and
distortion will increase significantly. For a more in depth level setting (gain adjustment) procedure, visit the Diamond Audio
website.
The HP or LP crossover adjustment can now be fine tuned. If you are using the amplifier in a HP configuration and would
like the system to be a little bit louder you can increase the HP Filter frequency and reset the "Gain" of the amplifier. Raising
the HP frequency up to high however will cause a loss of mid range and bass. If you are using the amplifier in a LP filter
configuration and you hear voice or vocals coming from your subwoofer system you can turn the LP Filter frequency down
(lower).
After setting the input gain adjustment and crossover, you may choose to add a small amount of "Bass Boost" (MICRO81U)
in the low frequency region. Remember that the Bass Boost feature will not fix a poorly designed subwoofer enclosure or
subwoofers that didn't sound good to begin with.
1. Make sure any bass EQ or low frequency equalization from the source unit is set to OFF or FLAT.
2. While playing the same musical selections used during the gain setting process, slowly increase the level of the Bass
EQ. You should be able to notice a change between 0 and +12dB. If you do not notice much difference, then it will
not serve any benefit to increase the boost further.
3. If the boost has audible benefits without adding appreciable distortion, find a level that suits your taste. Remember: it's
much easier to construct the right subwoofer enclosure for your listening preferences than relying on a bass boost
control to do the job!
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