Originally Posted by pdxrealtor
Another question- wouldn't that basically have the end result of being down 3 DB at 48 hz? Why boost if the end result is reduced power/output?
you can pull peaks down to some degree, but boosing is not recomended... well unless you have more than enough headroom to sacrafice a few db. However at 48hz its probably not that big of a deal compared to trying to boost frequencies below 20hz.
Here is a method I have derived from lots of research in a quest to achieve a flat response:
Try all placement options until you get the best response
Add room treatments if the response is lacking
If the response is still not ideal, then add more subwoofers
Last resort is eq'ing
Obviously not everybody has room for multiple subs and room treatments are not a option due to WAF. So folks resort to eq-devices such as anti-mode, mini-dsp, svs sms-1..etc. these are all great but some fail to realize that a eq device can eat up alot of headroom if the rooms acoustics are bad. Sure it will sound great at low volumes, but when you crank it up, one will find that the sub(s) are at thier limits rather quickly.
I found this out eq'ing my dual xv15's. I had a massive peak that was netting me 132db @ 30hz, but the rest of the FR range was 113-120db. When I pulled 12db out @ 30hz, I had to boost some frequencies on both sides to get flat. It sounded great at lower volumes, but I quickly found my output was limited to 115db and the sound quality was bad. So I decided to add another XV15 and my response is +/-5db from 80-16hz on a 90db sweep and sounds awsome! I watched Flight of the Phoenix @ -5db and it was unreal. The bass hit so hard it was bone jarring and I still had plenty of headroom.
Point is, If all it takes is pulling a few db here and adding a few db there to achieve +/-3db then you might not notice the loss of headroom. Also you may find that +/-3db is not neccessary and +/-6db may sound fine. Just play around some and see .