First off, I only payed 100 dollars for this subwoofer. The first time I listened to it, I smiled...it has a lot of power. Sound is pretty clean. Pretty loud, but when the bass hits, I hear this noise..i thought i just got scammed. So i played with it and put it all the way down 40hz, and I hear this loud distortion. I found out that it was coming from the port. (port noise). I pulled the whole port housing and i saw a net(screen) on the end of tubing (port) so i took it off. Guess what, it solved the problem..I turned it up @ 40Hz and the sound it pretty clean without any distortion...The only thing I dont like about it is the height...its sitting pretty high because they put the port right below the sub..and the bass is not that deep @ 40 Hz like subwoofers with ports mounted behind the box(sub) I think ports mounted in the back give you more bass, deeper, and give you that low deep bass. So if youre having probelems with it, i suggest you take the port housing off and take that screen off the end of the tubing..