It doesn't matter what brand, as long as it is good quality shielded cable. they are generally much thicker than the
normal dvd ones.
the best option would be to get a cable dedicated for subwoofer use. see link below...
Hi,
I had the same issue, its your RCA cable. try not to use a very long one and get a good quality shielded cable.
I replaced mine with a phillips high performance shielded cable. problem gone.