What you describe sounds like a mechanical noise made by the woofer cone exceeding it's excursion limits (although I'm just guessing.)
"Clipping" in the normal sense of the word is the flattening of the sine wave in a signal when an amplifier "runs out of steam", ie, it can't produce the required voltage. The power of the amp, the efficiency of the speaker, room size and placement, and of course listening level are all factors.
Hard to say what the exact cause is in your case. A bigger amp might help, but before you invest, I'd begin by 1) making sure your listening position isn't in an acoustic null (this would require you to really crank up the level in an effort to overcome room acoustics....a losing battle), then 2) moving the sub closer to a corner to try and take advantage of room loading to increase the acoustic output.
If you haven't done some research here on the 'gon or elsewhere on the net for some information on room acoustics and subwoofer placement, it's a good place to start. Proper positioning of the sub and the listening chair can make a huge difference in getting fast, tight. tuneful bass.
"Clipping" in the normal sense of the word is the flattening of the sine wave in a signal when an amplifier "runs out of steam", ie, it can't produce the required voltage. The power of the amp, the efficiency of the speaker, room size and placement, and of course listening level are all factors.
Hard to say what the exact cause is in your case. A bigger amp might help, but before you invest, I'd begin by 1) making sure your listening position isn't in an acoustic null (this would require you to really crank up the level in an effort to overcome room acoustics....a losing battle), then 2) moving the sub closer to a corner to try and take advantage of room loading to increase the acoustic output.
If you haven't done some research here on the 'gon or elsewhere on the net for some information on room acoustics and subwoofer placement, it's a good place to start. Proper positioning of the sub and the listening chair can make a huge difference in getting fast, tight. tuneful bass.