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Elevating subwoofer about two feet off the floor

Acoustic Sciences Corp recommends elevating the subwoofer about 2' off the floor http://www.acousticsciences.com/products/subtrap

see photo in link above ... has anyone tried raising their subs that high off the floor? Did it sound better?
tweaknkeep
emailists
923 posts
 
Wow I never heard of this product but thanks for bringing it up.
When I first got my velodyne dd10plus subs (I also sell them) I had a bit of trouble getting them to blend with my TAD CR1’S, which have very articulate bass. I had a pair of sisitrum stands 22" tall that used to use for a previous speaker (the TAD’s have their own stand) and on a lark decided to try them under the subs. No one could tell me if they would work or not since the subs were designed with the 6db gain the floor provides and in fact I was discouraged from doing so. I found the stands to be of great benefit and now have good blend with the mains, making much more in the room realism. And late night lowered level listening is enhanced by bumping up the subs level or using a lesser slope.
If anyone in the NY area wants to hear this unusual set up, PM me.  
stringreen's avatar
stringreen
6,494 posts
 
That's a surprise....I would think the floor refection would be helpful.
gdnrbob
4,471 posts
 
Interesting find. I can see this working with subs that are either light in weight or not constructed tightly-so that you can control the 'boomyness'.
I wish I could try a pair with my Vandy 2w's and see if they make a difference, but I have already spent too much on my stereo.
georgehifi's avatar
georgehifi
10,312 posts
 

I think you’ll find that "good" subwoofers are voice by the designers/manufacturers to take into account the floor (even wall) re-enforcement to get the FR as flat as possible in their operational range.

By raising them, they my very well roll off too early and maybe not give the low bass the were designed to do.


Cheers George

bdp24's avatar
bdp24
10,014 posts
 

Subwoofers "voiced"? There is no voicing possible at subwoofer frequencies. Danny Richie of GR Research addressed this issue recently on his website, in regards to the x/o mod he designed for the new Elac speakers. Voicing involves frequency ranges of larger swathes than a mere 90Hz (10-100Hz). Not even any tailoring, really, as woofers are crossed-over from at too low a frequency to allow or require that. The floor and wall reinforcement you mention effects all subwoofer frequencies relatively equally (in comparison with midrange and tweeter drivers) as far as the subs themselves go, though the dimensions of any given space have an enormous effect on the sound of all subs in that space. With subs it is pure output and room dimensions that are involved, plus non-voicing issues such as distortion at Hz at SPL, time domain behavior (as revealed in waterfall plots), mechanical issues such as motor power versus driver mass, enclosure resonances, etc.

If you remember the work Roy Allison did after he left Acoustic Research, he addressed the issue of floor reinforcement or cancellation from woofers located at certain distances from the floor in his Allison Acoustic speakers by putting the woofer at the bottom of the cabinet, and crossing over to them at a lower than common frequency, with the midrange and tweeter drivers put at ear level. He didn’t voice the woofer, unless you consider floor-loading voicing!

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