All right, so in the speaker set-up, I had originally set my Polk LSi9s to be crossover at 100hz. I am running a SMS-1 to control bass and I noticed that the LSi9s are playing down to about 40Hz on their own when the SMS (so the sub too) is muted. This is with the audio signal being sent as "stereo" from the set-up menu on the 970.

Any thoughts on this? Is it just a very slow roll-off? I have temporarily turned the cross-over up to 150hz so that the don't play below 70 or so hz, and I can dial in the subs more...

Doesn't setting the audio to Stereo bypass the digital section???...
Bill

Setting it to "bypass" would skip the digital section and bass management, at which point the LSi9's -3dB point of 50Hz would yield some measurable output down into the 40's. If you are in "stereo" mode you will still have the bass management in place, but there would be some output from the speakers even still.

I'd want to do the SMS-1 setup with the actual crossover that you will use. The purpose of the SMS-1 is to achieve a flat frequency response in the low frequencies - not just flat from the sub, but flat from the overall system of sub and speakers. The LSi9's will contribute something to the output below 100Hz, so you should let yourself include that contribution in the overall calibration.

All righty, I guess I just thought it would be a steaper cross-over...