Elevating subwoofer about two feet off the 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.   

I know this thread is old but I just raised my subs about 2 feet off the floor.  I use small Pinacle subs that are dipolar.  My idea was to get the subs out of the mess that is floor level.  

Right away there was improvement. At first I thought they were louder but now I don't think so.  Now I think they're just more integrated and clearer. 

It is just a frequency response thing. If you had room control you could make the woofer sound the same and be more efficient and probably go even lower. If you have control of frequency response on the floor or in a corner is always going to be better. But if there is a response aberration and lifting the woofer helps and you have no other way of dealing with it you are stuck.