I have a jl audio 1000/1 that I just picked up and did all the tuning recommendations with the ac multimeter. I'm also running an external active crossover set to 100hz and a 500k microfarad cap. The amp is running 2 mtx jackhammer 12's. The subs are hitting, then randomly there will almost be a feedback tone that comes out of the subs. Also the amp seems to not be reproducing certain tones. I'm more worried about the feedback tones. Can someone please help???

Car Audio & Video - Jl Audio - 1000/1 Car Audio Amplifier