I have the M60's. Yeah, I've calibrated with Avia and the radio shack meter many times. I've also had different systems and different rooms and the results are all the same. Flat tone controls sound exactly that, flat. To get any tactile bass or a sparkle of treble I have to turn up the main volume so high that it hurts my ears.
My basement room I use now is 23' x 17' and I've tried it all. I've tried the couch on a wall (2 different walls), couch 3/4 lenght of room back from the speakers, couch 1/4 lenght of room back from speakers, couch right in the middle of the room (I know that's a no-no) etc. Seriously my wife thinks I'm OCD when it comes to constantly re-configuring the room.
Thing is I have two other rooms with speakers set up (I have m3's in the living room) and those tone controls are up too. The tone controls are up in my car, the eq is tweaked to up the bass/treble in my classroom at school - it goes on and on.
I'd love to hear someone else's system that sounds great to them with the controls neutral with metal music playing. To me the sound is so small, almost clock-raidio-ish (well, not that bad but you get the point).
I've been a lurker/occasional poster here for years and I didn't want to admit all this...
