You're smart. That is a question you should ask. HOW? The correction is as good as the programming and the programming has parameters. It can't tune 4 separate subs from one mic reading. Nor can it tune 4 separate subs on one common amp output. BTW a servo sub is only as good as it's programmer is too. Zero reaction time is the key to all correction.
The better way is to tune the room mechanically first. I use a mic and SPLs via Helmholtz and proper room acoustics. Then worry about DSP. You won't need it though. A simple GEQ or PEQ will work much better. I use correction, sometimes and servo subs all the time.
There is something about DSP that sucks the life out of certain music. I have to tune by ear for that last little bit. DSP works better in a car or really weird rooms.