Yea thats what I don't get. I should not have enought power to get it to xmax around 30-35hz. The Freq is set to around 33-34 and the P-EQ is set from 1/4 from HI. I can have it at low volume and have it set to 0db gain instead of -12db and it will pop. Few test I use is the opening in Serenity (the very begining) and also Bolt right after she puts the coller on bolt. I can have it on med volume with it at 0db gain and it will pop at those spots. To me it seems the amp is giving some type of gain (boost) in that region.