it could be a indication of low amps.
Does it happen when car is running and lights are on?
If car is off do lights dim to the music at night?
You could be using more power than your
alternator can supply.
Most alternators are capable of producing 55-65 amps. This is adequate for sound systems producing up to 350 watts
RMS. Some more modern vehicles have alternators rated up to about 120 amps. This will be sufficient for systems of up to about 600 watts. Some
pre-1985 cars, on the other hand, have alternators only rated for 35 amps. This will only support about 125 watts in amplifier power.
One easy, effective solution maybe installing a capacitor. Heavy-duty capacitors connect to the power cable (just before it reaches your amplifier) and act as a buffer zone between your amp and your car's electrical system. They store up a reservoir of power which can supply the amplifier's peak demands (like a bass drum beat) without having to draw current from the battery.
First, Check your earth is excellent and not all clustered on one point. Ensure power leads are thick and secure.
Separate speaker and power cables.
Check auto turn on wire (thin blue on amp) is not connected to lights power source, use elect
aerial output on head instead
Run 4
gauge earth wire to car body near amp, power cable must be heavy
gauge too,
expessally with a sub woofer running.
