What are your exact settings for volume and low pass filter on your SVS sub?

I have a pair of the Micros behind my floor standing speakers (see virtual system) in a smallish room and I think mine are at -20db and x-over at 53hz, so in the same area as you and I agree with Doyle as well. 

I find that each room is different and the manufacturer specs on the lower response time rarely matters in-room.

If you are high-passing your mains, I might suggest using a higher cut off, around 80 Hz.  Especially with those low efficiency speakers (87 dB?) and, when ported, seal the ports.

Measurements uber alles. 

I have dual SB3000 subs paired with my Revel F226BE mains.  My volumes are 13 and LP is 120 to assist with the weak low end of the Revel 6" woofers.  I sometimes temporarily adjust the sub volume according to the source material.  My speakers are close to the rear wall but many feet away from side walls. The subs sit along side the mains and are facing around 45 degrees to the sides to keep the rear wall from acting like a bass resonator.

I have 2) SB4000’s  paired with Wilson Tune-Tots. I have the SVS output levels set at -3, but the whole system is controlled by a XTA DSP unit, using Audiocore software installed on a laptop. Crossover points and volume levels will vary somewhat depending on the recording but with most recordings the low pass is set at 173 Hz and the high pass at 177Hz with the sub output level set at +2.5 dbu and main output set at + 8 dbu.

I also have 2) non SVS subs being used as satellite subs with their output level usually set at + 1.5 dbu and their low pass filter set at 78 Hz.

Original poster here. We're starting to get a lot of variety now. I forgot to mention I have a bright, large, complex room and I listen to a variety of musical genres and route films through my system.

If I turn up the volume past -18 or so, there's way too much bass. If I go the other direction, the difference is more subtle. The helpful guy I talked to at SVS suggested ten Hz over the listed bottom end of my ATCs, even though this was based on -6db. By trial and error, that's what I've ended up with.

My sealed speakers do great bass in my system. They just don't go down as low as some, thus the subs.