I'm pretty new with the automotive audio systems so bare with me. I have 1995 BMW 540i completely stock. I have a 12" W7 subwoofer that is being powered by a JL audio 1000/1. I am running 4 gauge wires on both power and ground. Both wires are running straight to the battery since the battery is located below the back seat. I followed the instructions JL audio has provided to tune the amp. It has been working perfectly for a few months until now. Sometimes when I am listening to music at medium to high volumes the base will stop assuming the amp went in to protection mode. I would turn off the radio and let it sit for awhile then turn it back on. The base will start hitting again then turn off. When the base turned off once again, I was in the parking lot so i was able to get out of the car and see if the amp went into protection mode. Unfortunetly the green light was on indicating that it did not go into protection mode so I am now confused. Power and ground wires are brand new. RCA cable is kind of old since I did find it in my shed somewhere with all my extra wires. Can anybody help me? I am stuck at this point and I do not know what to do.
The amp may still be entering protection mode temporarily. What you describe is typically caused by one or both of two things: 1. your stock alternator can't supply enough current to feed that large of an amplifier, or amplifiers, and you need to upgrade your electrical system with a larger, high output alternator. 2. the input sensitivity (gain) on your amp(s) is set too high, causing the amplifier's input stage to be overdriven, and thus causing the amplifier(s) to clip, causing them to shut down to protect the speakers connected to them.
Get a multimeter from Walmart and check the voltage at the amplifier terminals, with the car on and playing you should average above 13V, with the car off, audio off any voltage below 12V means that the battery is not being charged properly or is in it's way out.
side note, when he says car on and off, he means the engine, not just the ignition in the accessory position. also, a battery can show 12 volts, and still be bad, as it often will show a surface charge of 12V, but under a load it fails. Autozone or similar can test the battery under load, for free. They can also test your alternator for free, too.