New Outlaw, pertaining to the Model 990... I never used the low pass filter (X-Over) in my previous surround preamp (RIP); I ran all speakers full range (even though they arn't) and set my sub to its lowest cut-off so that it plays 50 hz and below.

Maybe that was a mistake all this time. The 990 almost requires that the cut-off be used. If I want the sub to function all the time, I have to select "small" speaker. I was depressed about this initially - especially for the mains which can play below 30 hz. HOWEVER!, because the mains now don't even see anything below 40 hz, they do sound cleaner and faster.

The center and surrounds play down to about 46 hz - my center speaker is a big ugly monster. I tried the 990's 40 thru 80 hz cutoffs for C/LR/RR speakers and the 60 hz has the cleanest integration. I hoped to use the same X-Over for all speakers so that the sub doesn't have to try to reproduce a range of cut-offs to include the associated delays. Seems the sub wouldn't be able to handle the nuances of multiple time shifted excursions. I have the mains at X-Over 40 and the others at 60. Probably the sub is smearing the lows (*). If I had a fast and articulate sub, I might try to cut all speakers to the sub at 60hz, but as is leave the mains at 40 to help the sub to do less. For now, the limitations of the sub is driving my sound set-up decisions.

* - I don't know if the sub content is time delayed to coincide with the surround speakers. If the X-Over and below (that goes to the sub) is not affected by other speaker distances, that would be a cleaner tighter signal to arrive at the sub or is my thinking skewed?