Kenwood KAC-X812D - Manual (Page 8)

8 English
The acoustic properties of vehicle compartment tend to cause oscillation due to
resonance or unclearness of sound due to standing waves at certain frequencies.
The band reject filter can solve the problems of resonance or unclear sound
with minimum influence on the sound quality because it eliminates only the
frequencies causing resonance or standing waves. ■ Adjustment method:
The band reject filter cuts only the limited frequencies to minimize influence
on the sound quality. Therefore, its effect cannot be obtained unless the
cutoff frequencies are set accurately to the frequencies causing resonance
and standing waves. The band reject filter can be adjusted according to what
you feel through your ears, but we recommend the use of a signal generator
or a spectrum analyzer with a fine frequency measurement capability for the
adjustment.
• Adjustment using a signal generator:
Output a sine wave, vary its frequency to find the frequencies at which
the vehicle compartment resonates or volume increases (standing waves
occur), and set the "B.R.F. FREQUENCY" control to the position with which
the resonance and standing waves disappear.
• Adjustment using a spectrum analyzer:
Output white noise (sound in which all frequencies are at a certain level),
find the peak frequency observed on the spectrum analyzer, and set the
"B.R.F. FREQUENCY" control to the position with which the peak observed
on the spectrum analyzer disappears.
Band Reject Filter
Frequency
0 dB
Troubleshooting Guide
What might appear to be a malfunction in your unit may just be the result of slight misoperation or miswiring. Before calling service, first check the following
table for possible problems.
PROBLEM POSSIBLE CAUSE SOLUTION
No sound.
(Blown fuse.) • Input (or output) cables are disconnected.
• Protection circuit may be activated.
• Volume is too high.
• The speaker cord is shorted. • Connect the input (or output) cables.
• Check connections by referring to .
• Replace the fuse and use lower volume.
• After check the speaker cord and fixing the cause of the short,
replace the fuse.
The output level is too small
(or too large). • The input sensitivity adjusting control is not set to the correct
position.
• Adjust the control correctly referring to .
The sound quality is bad.
(The sound is distorted.) • The speakers wire are connected with wrong 9 / · polarity.
• A speaker wire is pinched by a screw in the car body.
• The switches may be set improperly.
• Connect them properly checking the 9 / · of the terminals
and wires well.
• Connect the speaker wire again so that it is not pinched by
anything.
• Set switches properly by referring to .
The sound does not change
even when you have changed
it with the Amplifier Control. • The AMP CONT has been turned "OFF". • Turn the AMP CONT "ON".
The set value cannot be
changed by the Amplifier
Control of the unit. • The AMP Control of the Center Unit is being used. • Release the AMP Control mode of the Center Unit.
The Amplifier Control cannot
be operated from the Center
Unit. • An incorrect ID number is used for the Master amplifier.
• The ID number of the amplifier has been changed. • Always set the ID number of the Master amplifier to "0".
• After you have changed the ID number of an amplifier, turn Off
the POWER switch of the Center Unit first, then turn it On again.