It seems to do 2 things then - follow the Fletcher-Munson curve but also augment the surrounds. They should have broken that up into boosted surround sound as it screws up the balance at -15 to -20db loudness that almost everyone listens to.
Why is there a DEQ 0, -5, -10, -15 with -30? Does DEQ allow levels?
I better find out as I just ordered a 4800h - the deal was too good to pass.
This generation not only allow you to control how strong you want the effect in general to be (that’s what the difference levels are, you choose a “reference” point for DEQ).
But it also allow you to tune the surround boost independently (the problem the the thread i shared complained about).
I’m very happy with Audyssey tbh.