Elevating subwoofer about two feet off the floor

Okay, so I pulled the trigger and purchased an ASC sub-trap. Will report findings soon.

I have my REL S5 on a Symposium platform which elevates it about 3"..It sounds much better than when on the carpeted floor..

Okay, coming back full circle to the beginning of the question: is it useful to elevate the sub? I bought a full round ASC tube trap that measures 20" diameter and 30" high. I placed the trap just to the right side of the right channel KEF LS50 monitor speaker and set an SVS 2000 sub on top. I think the result was phenomenal. Tight tuneful bass that was in the middle of the sound stage. You can see the tube trap here:  http://www.ebay.com/itm/371567367597?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Hmm tweak you must be in NYC since they were only doing local pick up.   I might have gone for these myself if I had seen them.   

Emailists,They have some for sale on another listing, but are higher priced.
http://www.ebay.com/itm/TUBE-TRAP-Room-Treatments-FOR-PICKUP-IN-NYC-/371636446080?hash=item568742238...