gonk & Mark - Thanks, guys!! I've definitely got some testing ahead of me now. As it turns out, I also have another subwoofer to test... a Martin Logan Descent that I picked up locally. Should be interesting.

Mark - regarding your comment...
Quote:

Keep in mind that the SMS-1 LF Cross needs to set at least as high or maybe slightly higher then the highest crossover point configured on the 990.
Naturally it's important to keep filters from 'stacking' and impacting one another. Fortunately the SMS-1 crossover CAN be disabled completely if needed, which is even better than fussing with the -3dB frequencies to keep from stacking the filters. It's not obvious in the menu, but it is covered in the SMS-1 manual.

- Jason