I installed a "Buttkicker" subwoofer in my car. It's a kind of heavy-duty piston that vibrates the entire metal surface of the car; you bolt it to the car floor. It's the same device they use in theaters - to provide very low vibrations that are FELT more than heard.
I bought an inexpensive, high-wattage subwoofer amp, and if the volume on it is all the way up, even without any input at all, the "buttkicker" gets to pulsing at about 120 cycles per MINUTE (or 2-3 per second), when there is no input or the input volume is low.
If input level increases, then this autonomous pulsing is replaced by proper response to the input signal, and the bass notes vibrate nicely. But that's only at high volumes.
Is there some kind of filter or some other measure I can take to eliminate this?
Is it perhaps a function of the long distance the input has to travel - along a good length of shieded RCA plug stereo cable - before it gets to the amp?
Thanks. I hope the explanation is clear enough.
Bob H.