Hi Austinbirdman,
Other things being equal--and in speaker design, they are rarely so--the bass extension of a given speaker, either sealed (acoustic suspension) or ported (bass-reflex) is a function of the internal enclosure volume and the woofer diameter. There are many trade-offs possible of course. You can get deeper bass extension from a small enclosure but you must sacrifice sensitivity--in other words, deeper bass output is possible but it you'll need a lot more power in watts to bring it to a reasonable volume level, and it won't handle dynamic peaks. You don't want a center channel with those characteristics! Given the dynamic range commonly found on Dolby Digital or dts soundtracks, as well as the range of DVD-A and SACD discs, peak power handling without strain or distortion becomes very important.
I know it's difficult to get your head around the idea that low bass energy at 80 Hz and lower is not locatable, but it is so. Thus with proper bass management, most of the deep bass energy can be directed to the subwoofer, whereras the locational cues are accurately reproduced by the smaller center and satellite speakers. The crack of a mallet against the drum head of a bass drum tells your brain where the sound is coming from--that sound is in the midrange--but the deep bass energy in the 20-Hz-to-30- Hz region is radiated by your subwoofer. When all this is combined, smaller satellites with a good subwoofer can reproduce very convincing and complex movie soundtracks and multichannel music of all types at relatively high volumes in average-sized rooms.
Regards,
