This is a very clever technique to build a set of EQs that mirror each other to drive a saturation plugin (this can be any saturation plugin you like) and emphasize different parts of the frequency spectrum, without causing crazy spikes in gain around the frequency you choose to juice up.
Does this sound confusing? Would this make more sense to just see someone build it? We would say yes.
Check out the video below to see how its done.
P.S. If you want this in a self contained plugin instead of having to chain together a few stock plugins, this has to be possible in Max for Live and we have our eye out for anything that can do it.