Most Musical Subwoofers?

I was wondering if any one had used/heard the Legacy Audio Extreme HD? Anyone compared these to JL Audio F-113 or F-112s? I'm considering adding subs to my system as my room has a suckout at about 40 hz that I'd like to fix.
Thanks in advance for any info/experience you might have. I'd be glad to discuss/talk over the phone as well. Send me your phone #.
Good listening,
If you have a large room you may want to consider 2 subs. (This was just discussed on a earlier thread). I have had great results with Rel over the years.
Good luck,
Another strong vote for Rel. Completely musical with the ability to be seamlessly dialed in to your system.
In my room, there is 35-40Hz suckout deal to bass cancellation at midline of the room. This is not present at 4 ft from the rear wall or 11 ft from the rearwall. Have you moved the seat backward and forward and remeasure? Is this present when you move the mic one to two feet off midline? How many db is it?

Sub may work too but better off minimizing the problem before adding the subs.