raising subwoofer off floor by 20 inches

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...