well, i turned down the bass a lil and it keeps doing that, the ampli is a mxa3002 MTX 300 rms, and the woofer is a mzs1204 MTX 300 rms, i dont know, i used to have an old sony xplod which didnt have a sub out, so i had to use the rear speakers out for the sub, and never had that kind of problem, its the first time, please help me.