In my opinion, people who own more than two subwoofers tend to over think about the need to independently EQ each individually. We all know that just move the sitting position for 1 feet will make a significant difference in the bass response curve anyway. If you use REW you will see it for yourself and would wonder how is the claim of any RC software/measuring technique can create a listening "bubble" for smooth and accurate bass response not against physics!! I am not saying there will be no improvement, but logically it is easy to understand either you create a somewhat compromised bubble or a narrower but more optimized mlp, but not a good size bubble that is optimized everywhere within it while also claiming time align each individual speaker/sub can make an audible difference. Wouldn't such simultaneous claims sound illogical and/or contradictory? I think there are good reasons why it took Dirac Live so many years to finally come up with this DLBC thing, the measuring side hasn't change, and the software, math involved are not rocket science right?
Yes in theory if you time align and EQ each of multiple, say 4 subs you should be able to achieve the following at the mlp:
Assuming DLBC can do the following:
Note: I say assume because there isn't much specific details on the Dirac website about how many subs can be time aligned, is it 4, or more?
1) All 4 subs will be time aligned so cancellation effects can be "minimized".
2) Each of the 4 subs will be EQ'ed individually.
Audyssey Sub EQ's:
1) Audyssey would require you to group the 4 subs into pairs of 2 based on pairing 2 that are equidistance to your mlp.
2) Audyssey sub EQ HT would time aligned the two pairs of 2 subs that are equidistance to mlp.
3) Audyssey XT32 would EQ all 4 as one.
So in theory DLBC is superior in the sense that Audyssey's grouping of two equidistance subs as one is not going to be exact but approximate only.
In practical sense, whatever effects DLBC can gain in terms of less cancellation due to timing/phase differences will depend on their software/algorithm, and such gain may be too low to be even audible when you consider humans ability to resolve the differences in bass response variations in the below 120 Hz range.
That's on time alignment, on EQ, it seems like a complicated analysis to determine if EQ each subwoofer when there is only one LFE channel is "better". It could actually be about the same or even worse, such analysis is better left to someone working on their PhD lol..
My gut feeling based on what I know and understand, DLBC, if done well, is superior in theory and in terms of minimizing cancellations between multiple subwoofers and therefore also overall efficiency and even in terms minimizing bass response variations between the listener's positions. That being said, I am very skeptical about whether one would actually gain in terms of perceived sound quality gain (vs Audyssey, Anthem, Trinnov, MSO etc. when listening to real world music, let alone movies.
I am also willing to bet that even after DLBC gain popularity, there will still be lots people heading for the minidsp+REW, or minidsp+MSO, read the marketing info and convince themselves there are major improvements over auto RC (Audyssey, Anthem ARC, DL etc..).
Such claims of easily audible, or night and day improvements over other's are to me, no difference those who claimed the same about differences achieved by comparing well designed/measured amps and dacs, that if you put them in the same room and do a properly conducted (say by Dr. Olive or Toole), their scores will be all over the map in the subjective scores and yet consistently in the below 60% better vs worse vs same objective scores.
By the way, I don't know if you have try MSO, that many swear by it's effectiveness in doing multiple subs. Since it is free, I would likely try it for fun, really for fun only, because I just can see any audible improvements over what I have now.
Multiple Subwoofers: Optimize Them With Multi-Sub Optimizer Software (diy-audio-engineering.org)
I am not biased against Dirac at all, in fact if and when DLBC becomes available for the PC standalone version I will likely try or buy it for my 2.1 system, yes only 1 sub but unfortunately without DLBC, the stereo PC standalone version can only do 2.0. I just think the whole Audyssey vs Anthem ARC vs DL vs Trinnov, minidsp and now MSO are overrated. One can stick with any of those, focus on doing it right and reap more benefits.