To get an idea of the xover slope, I ran some test tones and took a few "nearfield" (about 3 feet) measurements with an Aperion SPL meter (analog) at lower volume.
This was done with the sub disconnected, using Mirage OMD-5's connected to Gizmo.
Here's what I got:
123Hz - 84dB
107.2Hz - 83dB
100Hz - 82dB
79Hz - 72dB
70Hz - 68dB
So, down about 14dB from 100Hz to 70Hz. Theoretically, a 12dB/octave slope would give a -3dB at 100Hz, and be down an additional -12dB at 50Hz.
Considering the 12db/octave roll-off of the sealed OMD-5...which are rated -3dB at 60Hz, but probably start to roll-off a bit higher than that.... and Craig can correct me if I'm wrong... it seems Gizmo's xover is a 12dB/octave slope, which seems to be the standard slope used in most AVR's from what I could find.
With sub's over set around 110-120Hz:
45Hz - 80dB
50Hz - 87dB
70Hz - 91db
79Hz - 90dB
100Hz - 72dB
107.2Hz - 70dB
123Hz - 70dB
So it would seem the low-pass sub out xover has the same slope of 12db/octave.
In any case, this little experiment showed me that my sub doesn't reach down to stated spec of 35Hz at -3dB in my room. This could be a factor of my room of course, but I would think the room gain would help the low end and not result in "peak" in the 70-80Hz range. I don't know enough about room gain and boundary reinforcement to say.
Maybe Craig should just release that CS-10.1 in a 12-12.5" cube like he talked about...oke: The I will no longer need to care what the Aperion sub is capable of in my room.