How many agree that a rear sub is neccesary for a proper HT setup? Using a rear sub enables one to use LARGE speaker setting for rear speakers in the HT receiver/amp. In my experience, it widens and opens up the soundstage significantly and adds the resonace in DTS. Most DTS setups call for large full range speakers in the rear. By using a active sub, one can use bookshelf speakers for better imaging and avoid a logistical nightmare of placment. Also an active sub uses it's own power, thereby relieving the HT amp to give high dynamics to the rear speakers and leaving the power robbing job of bass to the sub. In my opinion, a rear sub is way more important than a rear center speaker.