One of the "experts" at AR (Terrence) has posted the following information: Power towers in and of themselves are not bad. The way Rob COULD use his would make him better off than most. Where power towers have problems is in the LFE. Because they are spaced, and the LFE is reproduced by both speakers, it is subject to cancellations at some frequencies. Its response will definately be rougher than a sub in a corner. However, If you were to use a sub for the LFE, and set you front towers(and only the front)to large, and your center to large(Rob can do all of this) you have the potential for a closer alignment to a movie theater setup. Spatially and timbrally, this is ideal because you do not move bass between 40-80hz that is eq'd for the center of the room, to near the walls. Anytime you do not have to redirect bass, that is a good thing. Especially considering all the processing that bass management requires. Cancellation comes from having more than one source producing the SAME information. Like what would be found if one used two space subs to reproduce the LFE. This can also be found in two channel setups were the vocals, and bass is reproduced by the two speakers. With three front channels reproducing bass within their OWN channels, cancellations cannot occur. One speaker is playing the bass from that ONE channel. Rarely, and I mean rarely will you find bass coming from all the front channels simultaneously, same amplitude, same frequencies. Engineers do not need to do that anymore. We now have the LFE channel if we want the bass to smack you in the chest. With prologic, if you wanted big bass, you had to put it in all three screen channels simultaneously. Movie theaters don't use bass management. Whatever the frequency response of the speakers is, thats what comes out of them. Having a sub on the LFE, your front L,C,R, on large, and the surrounds on small, mimicks the alignment of the movie theaters speaker system. There is no fear of cancellations because each speaker handles the output unique, and exclusive to that channel. So there is no real acoustical interaction that would produce cancellations. Setting the speakers to large, with a sub(s) handling the LFE will not create cancellations. Since the LFE is always 10db's higher than the center channel(or any one channel for that matter), it is unlikely to setup the conditions for cancellations. Remember, cancellation can only occur when identical phase, amplitude, and frequency of a signal is reproduced by multiple sources. The LFE at 10db's higher than the mains will not allow for that condition to exist. Each front speaker playing its OWN bass will not allow for that condition to exist.