Types Of Noise - Linear Power 5002 Owner's Manual And Installation Manual

In most any car, the possibility of picking up unwanted noises can be reduced if
the installation is done properly. Keep the system's wiring away from the
vehicle's wiring harness. Attach the ground for the amplifier to a clean, solid
portion of the body or frame. Use a good grade of shielded cable for all low level
signals.
Because of the astronomical number of possible noise problems, a detailed
solution to each and every specific problem is impossible. Here we will discuss
the major noise types, and try to proceed from cause to solution of each.

TYPES OF NOISE

1.Alternator noise: This is the most common source of noise, and expresses
itself as a high-pitched whine, which increases and decreases in pitch with the
speed of the engine. Unfortunately for sound systems, the cable between the
alternator and the battery forms a beautiful antenna to transmit the alternator's
noise to anything surrounding it.
2.Ignition noise: Ignition noise is formed by the primary and secondary ignition
systems in gas engines. It is characterized by a rapid ticking or popping noise
that increases or decreases with engine speed. The first form of ignition noise,
from the primary circuit, is caused by the points or solid-state circuitry that fires
the coil. These primary pulses can feed back through the ignition coil and into the
vehicle's electrical system. The secondary ignition circuit is composed of the
ignition coil, the spark plug wires, and the spark plugs. Since the secondary
circuit operates at quite a high voltage, and since this voltage is pulsed, it forms a
nice radio (noise) station under the hood. This noise is often transmitted to the
vehicle's wiring harness.
3.Accessory noise: Accessory noise is caused by the electrical noises formed
by the many electrical accessories in the vehicle. The most common noises are
the pops caused by high current switches (like the brake light switch) and
whirring noises caused by the various electrical motors in the vehicle (such as
the fuel pump or fan motor).
ENTRY METHODS
1. Radiation: Radiated noise is the most common problem found. As mentioned
earlier, the worst problem area is the wiring between the alternator and the
battery. The entire wiring harness can become contaminated if a portion of it runs
along side the alternator to battery cable.
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