Hello, thanks for your reply. Currently it's in a large open room, but I hope to move it downstairs into a smaller area in the next 6 months. I should do some measuring to look at different things.
About the filter- with the 20 Hz filter engaged, I hit Xmax with 50% gain watching blu-ray movies with very low bass. One in particular is "Tron: Legacy". When listening to music, I can use the 20 Hz filter without issue.
Do your Win ISD simulations take into account the bass boost the Oaudio amp has? I had been looking at possibly modifying my amp to reduce the boost, I got the information from Oaudio to do that if I need to. They have charts so you can set the boost from 1-5 dB of boost and the Fc from 22-38 Hz.
Switch Setting - 16 Hz C1, C2 = 1.00 uF
Filter Fc = 12.98 Hz
Filter Q = 2.41
Fc dB = 7.62 dB
dB Boost = ~10 dB
Switch Setting - 20 Hz; C1, C2 = 1.00 uF
Filter Fc = 17.33 Hz
Filter Q = 1.72
Fc dB = 4.71 dB
dB Boost = ~6 dB
Switch Setting - 25 Hz; C1, C2 = 1.00 uF
Filter Fc = 23.06 Hz
Filter Q = 1.42
Fc dB = 3.05 dB
dB Boost = ~4 dB
When I first built my sub, a lot of people suggested that I build it ported (after I had the box 80% complete). But they also suggested with more than 1 sub, sealed starts to get better. Probably because sealed enclosures don't have the excursion issues below tuning frequency that ported designs have. For the record my wife thinks my current 68L sub is "big".
My current thoughts are leaning toward building a 2nd sealed and going with the iNuke 1000 DSP; would be 300W per channel roughly. But of course I am open to other suggestions.