I recently built a sealed box for 2 eclipse 8200s. I hooked them up to a buttkicker BKA1000-4. They sound good, but when I turn the gain up on the amp and it hits a certain level, the amp starts to buzz when the subs hit hard. If i turn the volume down on my receiver then i am able to turn the gain on the amp up a little bit more before it starts making this sound. I was wondering if anyone has any ideas to what is causing the sound.