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ENG
ENG
6. Amplifier Interconnection
The following example shows the interconnection of a 4-channel amplifier. A suitable amplifier for the QM200.3 BMW sound system, is
e.g. the MB QUART amplifier with 4 x 75 Watts RMS and a matching filter section.
Please refer to the owner‘s manual of the amplifier to ensure the correct connection and operation.
Front panel
The channel pair CH3 / 4 must be operated in low pass-/band pass mode. After connecting the two bass speakers to the speaker outputs
CH3 & CH4 of the amplifier [ A ], set the controller of the low pass filter [ B ] to about 130 Hz. In order to use the optimum volume of the
bass speakers, it is important to use a high-pass filter and subsonic filter as well. Now set the controller of the high pass filter [ C ] on
channel pair CH3/4 to about 40 Hz.
After the installation of the midwoofers and tweeters in the doors and the connection of the crossovers, the signal inputs of the crossover
must be connected to the speaker outputs CH1 & CH2 of the amplifier [D]. Now set the controller of the high pass filter [E] on the amplifier
to 150 Hz.
IMPORTANT NOTE:
The midwoofers and tweeters must be driven in any case by a high pass filtered channel pair, otherwise the speakers could be damaged
with too low frequencies. To be on the safe side, set first the crossover frequency of the highpass filter [ E ] of CH1 & CH2 on the ampli-
fier, if possible, slightly higher than 150 Hz and then regulate down slowly and carefully.
At the crossovers, you are able to adjust the tweeter level in following steps:
-6dB
for a lower tweeter level,
-3dB
for a standard tweeter level and
0dB
for a high tweeter level
HINTS FOR SETTING THE LEVEL INPUT OF THE AMPLIFIER:
First, turn the two input level controllers [ F or G ] at the amplifier counterclockwise to the MIN. position. Now turn up the volume of the
head unit (car radio) to 80% - 90% of its maximum volume. Then turn slowly and carefully the input level controller [ F ] at the amplifier
back in clockwise direction, until you hear some distortions, then back a bit, until no distortions are audible. Then proceed accordingly
with the other input level controller [ G ]. The right volume balance between the channel pairs CH1/2 and CH3/4 should be selected accor-
ding to your taste and listening habits, but you should set the level controller [ F ] of the two bass speakers on CH3/4 a little higher than
CH1/2, so the bass develops a better performance.
Always make absolutely sure, that the audio signal of both channel pairs is not overdriven or distorted, when you turn up the volume
controller on your head unit (car radio), because this could damage the speakers permanently.
Rear panel
A
B
C
E
D
F
G
4. Mounting of the speakers
(Tweeters & Midwoofers)
Tweeter interconnection
to the mirror triangle
(Cable color red/silver)
Midwoofer interconnection
(Cable color blue/silver)
Interconnection/signal input
to the amplifier
(Cable color yellow/silver)
Installation option of the crossover housing
with the level adjustment switch for the tweeter.
The switch is located under the crossover cover.
Crossover interconnection:
E +/-
signal input to the amplifier
TW +/- tweeter
WF +/- midwoofer
5. Mounting of the subwoofers
To install the subwoofers, the front seats have to be removed,
which are secured with 4 screws. Loosen these screws and then
remove the standard speaker grille. Then replace the original
loudspeakers with the new MB Quart subwoofers.
To ensure a optimal and a free movement stroke of the speaker,
you may need to remove a portion of the foam. Set then the
speaker cover back to its location, and re-tighten the screws of
the seat, but please take care that these are tight.
