I am a bit late replying to your thread, as I have had a lot to contend with lately.
To put it bluntly, Dolby are certain that most people, mix engineers through to cinema installers and techs will screw it up if you add subs.
As you know I'm pretty anti sub on the whole and become more anti over time. I agree with Dolby 100%. Being certain subs are properly integrated is highly problematic.
When I designed my system one thing I was absolutely certain of was that I wanted a subless system. Time has proved my judgement correct.
I get increasing numbers of engineers here checking mixes. Most initially are awful. A major reason is mixing with sub satellite type systems with a sub on the floor and small monitors on the top of the mix console.
The result so often is not near enough oomph in the 60 to 600 Hz range and clearly monitoring with the sub too high.
It sounds awful because there is clearly far to much deep bass compensating for these small monitors that are just weak in the wind in the real power band.
These are now known around here as the speakers that do not lie.
So I send them off and the mix has often to be redone multiple times before the balance is acceptable.
I think we would be better off with speakers potent to 30 to 40 Hz range and no subs.
I'm unusual as I have that extra octave or so. This gives me the chance to see the havoc created by using subs while mixing.
As far as cinemas are concerned this would be a
high end set up. Using active crossovers of course.
It would take a massive horn loaded sub to to blend in the last octave with a system like that.
And just for the record I will say once again, that his forum is sub crazy and that the most dispensable part of an audio system is the sub or subs. The money would be far better spent on more capable main speakers.