So - would 2 subs - one for the front channels and one for the rear (or surround channel) be better for movies?http://www.audioc.com/library1/subprimer.htm
A single sub provides a major and cost-effective improvement for most people in most rooms with most music. However, there are a number of reasons to consider more than one sub.
-Stereo subwoofers, are more important if the main speakers need a rather high crossover frequency. Some very careful listeners may want stereo subwoofers with crossover as low as 60Hz while many others might be more than happy with a single subwoofer crossed over above 100Hz. Many of the popular three-piece satellite-subwoofer systems in the $500-$1000 range have crossovers above 160Hz! Some listeners hear the problems immediately while others never even notice them.
-Multiple subs can increase output levels and lower distortion. People with large rooms and those who need higher than average output levels might want to use more than one sub. Two smaller medium cabinets might fit your space better than one large box. For large spaces, and or very high volume requirements, any number of subs can be added to a system.
-Multiple subs can yield smoother in-room response than a single subwoofer. Loading the bass into the room from two or more points can give a better balanced bass throughout the room. However: if the crossover frequency is low, (usually below 80Hz or even lower), the best bass may be with the multiple subs placed next to each other.
-A third sub may be used for the rear surround channels. Many films now have significant low bass in the rear channels. Some processing modes require extra subs for the ultimate experience. Some film lovers feel that having a subwoofer for the rear channel improves impact and realism with such films.