My sub amp plays when it want sometimes a few seconds sometimes the whole song, sometimes no song. My battery was tested and said "bad battery" could that be my problem? I have no loose wires. The highs/mids amp doesn't do this.
Glasswolf its a kicker 800.2 amp on 2 cvr 12's which are 800w max each and 400w rms. If it matches, you're saying it can still go into protection mode? the thermal protection light doesn't come on when subs aren't playing. Amp was looked at by a professional technician and he said nothing was wrong with the amp but he didn't take it out and look under the circuit board. he just hooked up multimeter, sonar, etc. had it playing for a hour or 2 at low volume he said the amp is fine from how he tested it, he did say if there are small cracks under the board it can cause that. i hope its just the battery i have a yellowtop optima on the way. my 2500hd diesel has 2 battery, the power wire is on the right side passenger battery.
You should measure the voltage at the amp input terminals, if you see voltages like 10 or below when playing then your electrical is faulty and that could be anything including the battery.
I usually skip to state this as virtually no one seems to own a multimeter.
If you think your HU is malfunctioning, that is possible, is very easy to find out, just connect a portable media player to the amp for a while, if you have no interruptions then the HU may be the problem.
the power handling of the speakers means nothiing. That's simply a measure of how much heat, measured in watts, that the voice coils can handle without physical thermal damage. It has absolutely no relation or correlation to how much power the speakers need to reach Xmech or Xmax, or their physical limits of output. The gain setting on the amp controls the input stage of the amplifier, matching that input stage to the line voltage presented to the amplifier, since different sources have different line voltages (200mV, up to 16 volts) If all head units supplied the same line voltage, you wouldn't need a gain, or input sensitivity setting.
If the gain on the amp is set too high, then the input stage of the amp will be over-driven, causing the sinewave signal presented to the amp, to be reproduced as a clipped wave, which sends DC voltage to the speakers. This is what builds heat in voice coils, and damages speakers. This also heats up the amplifier, and can cause it to enter thermal protection.
You can cause these same issues by having a weak charging system (bad battery, bad ground, too small power wire, etc)