【 Weak current College 】 car audio noise removal method

When using a car audio or replace the audio, the audio will produce more noise, noise can affect the sound quality, the lower the audio indicator, or even the entire sound system cannot listen for noise issues, the introduction of noise sources and basic troubleshooting.
First, the source of noise
Noise from the following channels into car audio system.
1, invade the power cord (through the host and the amplifier power cord into the system).
2, through the Earth's current (via xxx ground and power amplifier of the ground).
3. subject to other wire harness induction (via xxx receive and original car harness induction).
4. electrical interference (electric Horn, motors, etc.).
1, 2, 3, there is a correlation.
2. meet noise countermeasures
Generally deal with the noise-to-use components, automotive capacitor or coaxial motor capacitors (particularly effective to deal with high-frequency noise), Earl flow ring (ICP), LC filters, grounding, diodes, etc.
1, against ignition system noise
Check ignition coil cathode on the capacitor is installed, such as installation check capacity is reduced, if size reduces Platinum-contact easily spark erosion, interference, you need to replace the electrical capacity of 0, 5UF/400V promise of capacitance.
Check ignition voltage is using carbon fine line, if you use wire-prone to interference, which is a radio interference, so the parts must be replaced.
You can increase the damping resistance, noise suppression sparks by 1 megohm resistance concatenated output main high-voltage ignition coils, reduce interference.
2, the motor noise removal
First audio equipment and signal cable from the motor and motor line, available 1 only promise of capacitor in parallel at both ends of the motor, you can also only with 2-line in motor inductor respectively and cathode ray, then 2-polarity motor Capacitor respectively in the positive and negative cables, on the other side of the Earth form filtercircuit that spark of absorbing carbon brushes so that the noise reduction.
3, no relays electric Horn noise, exclude method has the following main categories:
In one of the speaker terminals on the ground and then a capacitor.
-In one of the Horn of a Terminal first-line to ground inductance, and received a capacitor.
In the two speaker terminals on the use of method-respectively.
In the steering wheel of the loudspeaker button-contact a capacitor between parallel.
4, the relay electric Horn noise, exclude method has the following main categories:
Electric Horn bracket and body should contact good.
-In relay contacts at both ends, a capacitor in parallel, or in contact with both ends of a capacitor in parallel.
? Use 3,? and ˉ method.
5 grounding bad will produce noise.
If the hood failed to secure the entire earth, bonnet becomes a xxx, the car noise radiation produced by ministries to the surrounding space and from xxx and the circuit into the audio system. Bonnet and body equipped with a connector, required to land on paint, grease, dirt, etc. are completely eliminated.
Engines (engines) and the body, or between front wheel suspension, body, between exhaust pipe and the body should have a good connection.
6. power cable noise suppression:
To effectively eliminate power line noise, should put Earl flow ring * near power amplifier installed. If there is a lot of power amplifiers, each power amplifier is installed near a stream circle because Earl noise from a power amplifier to another, so that a single failure of Earl flow ring.
7, to the signal cable (RCA) incoming noise suppression:
Signal cable should be located away from power cables and power cables are installed on both sides of the body, so that you can avoid the possibility of interference. The signal cable is double shielded network, you should put the outer shielding network attached to the chassis.
In practice also encounter many problems, but the important thing is to find the source of interference, then the remedy to solve it, so that the car audio system for playback of each program are clear and pure perfection.
Noise is the car audio fault because most and more difficult to troubleshoot because the vehicle's structure and lines of more complex, easy to place a lot of noise, so you should have some auto circuit and car audio knowledge, troubleshooting can be handy.
Solution: first of all, according to the noise analysis and judgement by principle identify failure is part of, and then take different exclusion method.
Simple exclusion approach, first listen to the audio of the radio, tape and CD part are the noise, if you have to check the power cord, Earth wire, signal line, the alignment of the parts is reasonable, the signal line whether with or without loosing ground breaking the skin, the power amplifier should be insulated with the body. In response to different noise sources, take different measures for processing, if the noise cannot be excluded, is to generate noise signal source disposed before the measures taken against noise, so that we can resolve the noise.