Have decided to try building a sub for my system and am looking for some recomendations. This sub will be used for Home Theater/ HDTV only. The only music we would listen to with this system is the music in the actual broadcast/dvd. The sub is primarily needed for special effects I guess. We really want it to blend in for other aspects of viewing. The one I have now is cheap and really boomy and the wife is constantly complaining, mainly during HDTV viewing. Have tentalivly picked a Quatro in either a 12 or 15 inch. The 15 is on sale now for about the same as the 12. Problem is size needs to be limited somewhat. Not more than an 18X18 inch footprint, but can go vertical a little bit. The box designs on the PE web site show a ported for the 12 at 17x17 and a sealed for the 15 about the same size. Which one would be better for my application? Along the same lines, what amp would work out the best? Was looking at the 240 watt. Other recomendations would be appreciated if something better than the Quatro in the same general price catagory.