I listened to a Dead Can Dance disc at the local Magnolia (hi-fi shop), and they had a VERY large and pricey Rel subwoofer in the mix. Holy shnikes! A big bad sub pressurizes a room. It's really amazing. Obviously you don't need it to hear a bass guitar. It's for all the sub-level background noise. From my experience, it really can transform a listening experience.

I just need to figure out how 1) I can afford an EP600, and 2) how do I convince Roger we need one.