REL is always a good place to start, they make great Subs, also check out ATC, they make wonderful subs as well. Both of these subs have the tune and rhythm to keep up with your speakers.

Hi Patrick

I am using a velodyne hgs-18 with my ProAc response fours and you really can't tell there's a sub in the system.
I quess the newer models dd-18 with their integrated parametric equaliser and mic should be better. if you think a dd-18 is too expensive or/and an overkill in your system, go for the dd-12.

Good luck !

For music, I'd suggest a sealed sub. . . vented boxes just don't make it for me, especially for music (I don't even like them for HT).

I always like to throw out the DIY option for subs. I'm a wreck when it comes to woodwork, but a sub is easy to manage, especially if you use an outboard amp and crossover--you're building a box with holes for a speaker and a pair of binding posts. You can sink the bulk of your money into a good driver. MDF is cheap, and you can even have large pieces cut at places like Lowes and Home Depot.
Best subs for the money IMO,
-->grub

What kind of interconnect and speaker cable are you using?

You have 802s and subs already and you need more bass? Are you trying to fill a football stadium?
Seriously, I can't fathom a listening room the size you must have this setup in. Still, I guess 27hz is relative to how well it is articulated and the size of your room.

I would be curious as to what you come up with...let us know.

Quote:
For music, I'd suggest a sealed sub. . . vented boxes just don't make it for me, especially for music (I don't even like them for HT).

I'll 2nd that recommendation - I have no use for vented subs. I'm using a modest Wharfedale sealed sub and you cannot tell it is in use except when you turn it off!