DLS MRA22, Manual

Page: 5 / 14

Crossovers
Input Level control
The input level control, 5V – 0,25 V,
matches the output of your radio to
the input of the amplifier. After instal-
lation is complete, make sure the in-
put of the amplifier is turned down all
the way ( counter-clockwise at 5V ).
All amplifiers include high pass filter
( HPF ) and low pass filters ( LPF).
All filters are continously variable and all filters can
be switched on and off. MRA31 also include a
subsonic filter.
Low Pass Filter (LPF)
The LPF (low pass filter) mostly used for
subwoofers. It will allow low frequencies only and
blocks higher frequencies. A typical setting is 50 –
80 Hz. The filter can be switched in and out.
This is normally used for subwoofers
On
MRA41 the filter can also be used for active
crossover in a 2-way speaker component kit, a
typical crocssover point is then 3,5 - 4 kHz.
5
Play a tape or CD, make sure all bass or treble
settings or equalizer are flat, and turn the volume of
the radio up until you just start to hear distortion.
Turn the volume control down just a bit. On the
amplifier increase the input level control ( clockwise
or to the right ) until you just start to hear distortion,
then back the level control just a bit. Now your radio
and amplifier levels are matched.
The phase control on MRA31 can be set
continuously from 0 - 180 degrees. This is very
useful when you want to adjust the bass sound for
best front stage image. Start on 0 and turn the control
slowly clockwise until you experience that the bass
sound is coming from the front. If you dont get the
result you want, also try to
phase reverse the subwoofer
connections and make
a new adjustment.
NOTE: This function is intended for car use and
may not be fully functional in boats. Set the control
to 0.
Phase control MRA31
0 180
PHASE
Subsonic filter MRA31
The Subsonic filter blocks the very
deepest frequencies from reaching the
subwoofers. It has a fixed frequency
of 25 Hz and can be switched On / Off.
For sub channel C only.
Level
5V
0,25V
LPF
Off On
80Hz 200Hz
50Hz 500Hz
Filter frequency range:
MRA22: 50-500 Hz
MRA31: 50 - 120 Hz
MRA41:
Ch A/B: 50(500)Hz - 500(5k)Hz
MRA22, MRA31, MRA41
Subsonic
Off On
Grand bass on MRA41
Grand Bass is used to increase the bass volume
at an interval of bass frequencies. You can select
the center frequency between 25Hz and 80 Hz and
the amplification between 0 dB ( no amplification )
and 18 dB ( full amplification ).
The slope of the filter is 10 – 12 dB at maximum
setting.
This function is used to compensate for the bass
box function and to adjust for your own taste of
bass. Set level control at 0 dB if you want it to be
inoperative.
The HPF (high pass filter) blocks very low
frequencies from reaching the speakers. It is mostly
used at say 60 Hz to protect small speakers (like 6
inch and smaller) from deep bass. It can also be
used as subsonic filter to take away the very
deepest frequencies from a bass box. The typical
setting is then around 25 – 40 Hz.
The filter can be switched off if you want to run the
amplifier in full range mode.
On
MRA41 the filter can also be used for active
crossover in a 2-way speaker component kit, a
typical crocssover point is then 3,5 - 4 kHz.
High Pass Filter (HPF)
Filter frequency range:
MRA22
: 15-150 Hz
MRA31 : 50 - 150 Hz
MRA41:
Ch A/B: 15 - 500 Hz
Ch C/D: 15(150)Hz - 500(5k) Hz
Grand Bass
40Hz 60Hz
25Hz 80Hz 0dB 18dB
HPF
Off On
50Hz 220Hz
15Hz 500Hz