Professional Tips - DLS Reference ACW68 User Manual

Professional tips

NOISE PROBLEMS
WHINING NOISE VARYING WITH
ENGINE REVOLUTIONS:
Do this:
1. Rewire the power supply (12 V) to source
unit direct from battery.
2. Rewire ground wire from source unit to
clean position on chassis.
3. Check all power connections to ensure
that they are clean and tight.
4. Check quality of system ground connec-
tion.
5. Install a Power Cap capacitor. This can be
helpful against most noise problems.
CONSTANT WHINING NOISE:
Do this:
1. Ensure that all equipment has a common
ground point.
2. Check quality of earth strap connection
from battery negative terminal to chassis.
3. Disconnect signal cables from amplifier to
see if noise disappears. If so the leads are
picking up noise. Test this by laying a new
cable over the seats and reconnecting to
the amplifier. If the noise does not return,
re- route original cable away from source
of interference.If noise remains regardless
of cable position, try to use so called
Quasi-balanced signal cables. DLS
PRO-cables are Quasi-balanced.
INSTALLING IN TRUNK
When installing the amplifier in the trunk, run
the power wires along the same path as the
other vehicle wiring. Many cars have insulated
channels for wiring. you will have to remove
the door sill trim and the carpet.
SPEAKER POLARITY CHECK
All speakers in a car audio system should be
connected in phase (the same polarity). All
speaker cones must move in the same
direction. Out of phase speakers will cause a
lack of bass, and a poor stereo soundstage.
Checking polarity:
Hold the connection of the speaker wire to
the terminal of a 1,5 Volt flashlight battery.
Tap the + wire on to the + terminal of the
battery, and observe the movement of the
cone. The cone should move outwards when
the wire touches the battery, and inwards
when the battery is removed. If it is the other
way around, the speaker has been
connected backwards and it must be
removed and connected correctly. If your
system also has a subwoofer connected
through a passive 6 or 12 dB crossover, try
to connect this with various polarity and
judge what sounds best. The phase shift in
passive crossovers sometimes makes it
necessary to change polarity.
+
Battery
1,5 Volt
-
NOTE! Tweeters can not be tested this way,
double check the connections instead.
SPEAKERS AND POWER WIRES
Do not run speaker and power wires next to
each other. Power wires can generate a
"siren" sound in the speakers. Run speaker
and power wires on opposite sides of the car.
9
+
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