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Professional Tip:
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 connection.
5. Install a power capacitor with connections as
close as possible to the alternator. This by-
passes the noise at source and eliminates
many issues with noise problems. In cars with
a jump start connection, this provides a con-
ventent connection point for the capacitor.
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, reroute original ca-
ble away from source of interference.
If noise remains regardless of cable position,
try to use so called Quasi-balanced signal ca-
bles. DLS PRO-cables are Quasi-balanced.
Professional Tip:
Installation in the 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.
Professional Tip:
Crimp connections
Purchase crimp connectors and crimping tool.
Connectors are color coded.
1. Strip 1/4 inch (6mm) of insulation from the wire
2. Insert into connector
3. Crimp tightly
11
Professional Tip:
SPEAKER POLARITY CHECK.
All speakers in a car audio system should be con-
nected 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, dou-
ble check the connections instead.
Professional Tip:
Securing wires
Use wire ties to bundle together when possible.
(But never bundle speaker wires or signal cables
together with power wires).
Professional Tip:
Speaker 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.
+
-
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