raising subwoofer off floor by 20 inches

i was told by an audio dealer to raise my sub off the floor by 20 inches to achieve better impact/punch and smoother blend with my mains. is this setup worth searching and paying for a sturdy stand? are there any high quality subwoofer stands available?

i would greatly appreciate you sharing your experience. thanks!!

Sounds odd to me. Most sub's are designed to be on the floor. Raise it that far off the floor and you'll probably screw up the bass by creating a large suck out.

Exactly whats your problem anyway. List your equipment, room dimensions, speaker locations, listener position and perhaps some one can give you some specific help.
I don't know about such a plan. Is it a downfiring sub? If so, it probably should be on the floor. As far as blending better with your mains, try lowering the crossover point. If you want more punch, turn the sub up or place it in a corner.
I just looked at your system. Your bass graph shows some fairly flat bass. Where is it crossed over? All I can see is an expected droop below 32hz and another droop up about 200hz. What am I missing. Are you trying to get more bass on the 25 to 32 hz area.

I noted some control sliders on the graph - are these actually equalizer controls that you have used to get the bass response that you have? I'm confused (nothing new).
I remember seeing an article in one of the rags about a subwoofer stand. I only skimmed it, but I do remember that they did think it made an improvement. I don't remember what sub they were using or anything else. When I get a chance, I will look for it again.
All subs should be off the floor by approximately 27-31 inches. This idea is from ASC (the tube trap people). It works by minimizing standing waves as low frequencies and providing better coupling of the woofer drivers with the room. ASC makes a special tube trap to elevate your subs off the floor to take advantage of this idea.

I should note that the height off the floor and distance into the room can vary depending on ceiling height.
thanks guys for your comments!

i am actually quite content with my setup. the suggestion came up during a casual conversation with a velodyne dealer (i was trying to get a good deal on a second dd-12). so i figured why not ask my fellow audiogoners before i try out the placement.

Newbee, i am sending full signals from source to both main amps and subwoofer, which is set to respond to 60hz and below. the sliders are indeed equalizer adjustments made to achieve the somewhat flat response. my current goal would be to achieve similar or better results without adjusting so much of the equalizer settings.

thanks Hifidreams and Etbaby for your info. the asc subtrap is quite interesting.
>>All subs should be off the floor by approximately 27-31 inches<<

Really? On what empirical data is this based? Interesting that Velodyne, Vandersteen, Kharma, etc. don't recommend this, only ASC. I'm sure it has nothing to do with their special tube trap that elevates the sub.
Szutinglee, Have you tried moving your listing position and speakers a bit. Some times we locate them in a null or a node which results the the uneven response indicated by you equalizer settings. Some times not, its just the room dimensions. You might also get a smoother response just by moving the sub around as well.
Just for fun, you could put the sub on a chair or a small table and see if you notice any difference in the bass.
I was talking with someone awhile ago about this very issue. It's probably considered a bit tweaky and cumbersome to elevate a subwoofer, but the reasons supporting this idea have something to do with the actual height of low frequency sound waves. They are much larger than higher frequeny waves and, as such, half or more of the sound wave is being lopped off by the floor when a sub is at ground level. This may or may not be a 'real world' concern of course...
I have heard of this technique also, and for the same reasons mentioned by Centurymantra. If the stand you speak of is easy to come by/construct then it would be worthwhile to try.

Now WAF... that's another matter. Maybe you can paint some fish on it and call it an aquarium.
i have very limited speaker placement options due to the system being in the livingroom/kids' playroom, which is 25'L x 15'W x 10'H.

raising the sub would make it look quite ugly and awkward. but you guys got me interested enough to try it. unfortunately, i don't have anything in my home that i can use to elevate the sub. so the search begins...

thanks again for everyone's input.