emmersive sound

["Qua and Vishara Veda" <exalted@easystreet.com>]

I have a project in mind that calls for  to creating a sound experience for
listeners that feels full-bodied and emmersive, even at low listening 
levels
in a small venue.  The source material could include a live instrument(s)  
,
possibly Stick, bass, synth, some with stereo effects,  as well as some
recorded music.

At first I thought I might need a pair of good sized cabinets, feeling that
I'd need a good amount of low-end to support the 'emmersion'.  But I'm
considering 2-4 dispersed, relatively smaller cabinets as an alternative.
Quite a few pro/cons for each, I'm sure.

What would be some of the most important elements to achieve this effect?
Reverb/delay?  low-freq.?  (quasi)multichannel?  other?

thanks,
-Qua