After locating the best place for sub in my room (by crawling on the floor), I still wasn't satisfy with its performance regarding different type of music or movies. My listening habit vary greatly from County, Blues, Rap, R&B to Rock and Reggae. On some type of music, sub sound seem to be perfect with right amount of bass and thump. But on other types of music such as R&B, the sub just takes over the main speakers and I find my self keep tweaking sub level to bring it in line.

Any way after a while, constant tweaking of sub's level gets very old (especially if you have a cigarette in one hand and beer in the other ), so a solution was needed.

So I stuck a big sock in sub's port hole (down firing), adjusted the sub's level accordingly, and now the thumb seem to be gone. The sub seem to be giving more "linear" performance over great range of music types, especially with heavy bass music such as rap or reggae. Without the porthole stuffed, the porthole output (frequency response) was much louder than sub's speaker output, and when slightly pushed, the porthole sound took over more delicate sound of the mid bass notes coming from the sub.

So now with sub porthole being stuffed, the thumping is gone (even with rap), and bass notes (especially the mid bass) are more distinct and refine, and I don't have to get up tweaking anytime there is change of music genre