In trying to get MSO and the Mini-DSP to work nicely with my AVR with mains integration as well, (i.e. not a sub-only configuration), I set just one filter for the mains at set it at 180Hz and with a minimal boost of 0.1dB and a very narrow range, and did not have a delay block. So when MSO optimised the response across my 3 subs AND the mains, I got a -ve common delay block for all 3 subs, then no delay on one sub and some delays on the other 2. For the -ve common delay block for all 3 subs, I increased the Sub distance in the Amp to correspond to the delay amount, then added the 2 sub delays into the Mini-DSP.
I found out two things:
(1) The Denon AVR has a maximum distance of 6m between any two speakers /sub set up! I had just come across this in the AVR as the nearest speaker was shown as 1.0m (behind the MLP), and the sub was shown @ 5.8m (in front of the MLP). So in theory the max distance I could then goto on the sub was 7m (6m plus the 1m closest distance). Dialling in the added distance on the sub setting just bumped up against this limit!
That aside, the sound was brilliant! I thought I may have stumbled on a way to get subs and mains optimised with a little lateral thinking on the mains filters for the MSO calcs!
(2) Although the 'integration' calculations were optimised I found this next problem equally applied to the subs-only configuration! -- the delay on the Sub channel was such that in effect a 'lip sync' type issue occurred on frequencies below the 80Hz crossover! Was watching a film where there was a large impact which rattled into the sub frequencies and just as I can discern a few ms differences between sound and picture for speech and lip sync, the same was true of the 'impact'! The sound was definitely 'too late' for what I saw on the screen! Very disconcerting if the truth be known! So in order to get the 'sub' to be better aligned by not having so much delay in the sub channel, it would mean getting the sub signal to be 'earlier' in terms of the mains speakers. I.e. a negative delay. But that translates to an increase in distance on the sub channel in order in effect to add a net positive delay on all the other channels. But as I was already up at the limit of 6m, I couldn't do this. So in order to get correct timing between sub output and on-screen action, I would have to ignore the delays that the MSO would calculate, even for a sub-only config and optimisation. And that being the case, one may as well not run MSO and Mini-DSP as any manual delays added to the AVR will just throw a spanner in the overall result.
How would this challenge be best overcome to achieve a great response and yet maintain sync between sub and screen action?