Quantum QL812SP, Owner'S Manual

31

ENGLISH

DISTORTION OR HISSING NOISE CAN BE HEARD FROM THE SPEAKERS
Check the following steps:
Is a input level controller on the device set too high?

Slowly turn the controller back until you hear a clean audio signal.

Is the Bass Boost controller on the device set too high?

Slowly turn the controller back until you hear a clean audio signal.

Is the loudness function on the head unit set too high?

Deactivate loudness or turn the loudness setting back until you can hear a clean audio signal.

Are the EQ and sound settings on the head unit set too high?

Turn down the settings for Treble, Middle and Bass or deactivate the equalizer until you can hear a 

clean audio signal.

ENGINE SPEED DEPENDENT NOISE CAN BE HEARD FROM THE SPEAKERS
Check the following steps:
Have the RCA cables been laid separately from the power cable in the vehicle?

If necessary, lay the cables again and make sure that the audio cables are laid separately from the 

power cable on the left and right in the vehicle.

Is the device’s ground connection correctly connected?

Make sure that the ground connection of the device is not connected directly to the negative pole of 

the vehicle battery. Select a suitable ground point on the vehicle body for connection. If necessary, use 

contact spray to improve the conductivity of the connections.

Is the conductivity of the ground cable from the vehicle battery to the body okay?

Make sure that the ground connection of the vehicle battery has a stable and conductive connection to 

the body. If necessary, use contact spray to improve the conductivity of the connections.

AN ACTIVE OPERATED TWEETER IS DISTORTED OR CRACKED
CAUTION: Tweeters will be damaged if the frequencies are too low. Please note the manufacturer’s 

information on which frequency setting is recommended. To be on the safe side, pause the play-

back of the head unit first. Check the following steps:
Is the crossover mode switch of the relevant channel pair on the device set correctly?

Set the crossover mode switch to the high pass position (HP or HPF).

Is the high pass filter of the relevant channel pair set too low on the device?

First turn the high pass controller fully clockwise. Now start playback on the head unit. Then turn the 

high pass controller slowly counter-clockwise until you can hear a clean sound from the tweeters and 

produce a balanced sound together with the woofers/mid-range speakers. Make sure that the woofers/

mid-range speakers are set correctly with the respective high pass and low pass controllers.