MBQuart QM200C BMW Montage Und Installation Seite 5

6. Amplifier Interconnection
The following example shows the interconnection of a 4-channel amplifier. A suitable amplifier for the QM200C BMW sound system, is
e.g. the MB QUART NANO NSC475 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.
Frontpanel
of NSC475
Rearpanel
of NSC475
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.
E G
B C F
D A
ENG
5