This means first fixing the room’s acoustical problems (most always the bass errors). Since mine cannot be obliterated like a man music cave I use a bass room correction DSP device and an SPL meter to work towards a flat response, and a bit of very judicious digital equalization. Unless the recording is crap, my main speakers always ‘disappear’. They could be run sans subs for most music.
The room correction DSP is very effective. The REL B1 ‘disappeared sonically in my listening position, low crossed at 25Hz or so with low volume to supplement the D2s deep low response (w/limited dynamics, for some). I also enjoyed the spaciousness a good REL sub-bass system can provide (even one), even on non-bass material.
BUT, based on the above posts, I lugged subwoofers upstairs and downstairs this week and reset the main audio listening/living room (20w x17 x10, three SVS subs), the basement home theater (12x22x8: REL B1 & Def Tech PF-1500, old 15”), and the upstairs TV room (13x16 x9 using singe REL Storm III very successfully with Elac Debut 5.2 system).
The SVS SB-3000 went into the old REL B1 spot (right front corner) as it was demonstrably the ‘invisible spot’. The two SB-2000 units (all 3 are sealed) went onto left side wall and the rear wall, semi-asymmetrically (as much as this room would allow with two large openings). SB-2000s only low pass to 50Hz so that’s where they stayed. Also set SB-3000 to 50Hz and at low volume (half the time testing I had fingers on cones to be sure the subs were on; they were…).
From 100Hz to 31.5Hz the 1/3 octave frequency measurements (80dB volume baseline at 200Hz) were between 81.5dB and 80 (at 31.5Hz). I was pleased and initial thoughts were increased solidity at the extreme bottom end along with more oomph when required. I heard no bass where it was not before. I want to do more listening with subs off and on as the difference in apparent openness is a bit subtle at the modest volumes.
I suspect perhaps better physical positioning, phase setting, and general integrating will help even more. The SB-3000 offers a cut-off down to 30Hz as well as some additional parametric equalization for the single sub only. Perhaps working with all of these variables would dial it in better. Like others I do not see myself going back to one sub (probably more like looking for my 4th SVS and making a 10ft high real-wall mount for one of them…). Thanks to all. I’m a DBA believer.
p.s. Thanks to Duke for bringing up the Fletcher Munson curves. For those of you that still don’t quite get it; it seems to be the reason the “Loudness” button was invented.