christoffeldg:
Welcome to the AH and I hope you enjoy lively discussions. I just read this entire thread and I think its starting to get wrapped around the axle a bit. After about 10 replies, that is inevitable.
I own a Denon x4200w AVR. In several of your replies, I see you mention background noise as a problem and a distinction. On my own x4200w, there is no background noise. I operate in a near field sound setup and if there was background noise, foreground noise, or noise in the attic, I'd hear it since I'm practically sitting next to my speakers. I hear no noise: just music. If there's no music: there's no sound.
Is there a difference with the Audessey turned on and off? Yes. I would be terribly disappointed if my room correction software didn't do anything audible. Some days I run in pure direct mode: no DSP at all. Having my DSP on or off changes how the music sounds: but it doesn't have anything to do with this "background noise" you refer to. I don't have background noise that's audible.
@TLS Guy put in a post on your topic. So did
@PENG . Between those two fellows there is more concrete knowledge and experience with amplifiers than any pair of voices I could name. You may not know them because you are new to the AH. Others here know them however. I think what they've posted is pretty solid information. If you disagree with their viewpoints, you are welcome to do so. You are entitled to an opinion. I'm gonna go with TLS_Guy and Peng on this one.