@mahgister it appears to me that you have gone down a BAACH 3D Sound rabbit hole. Yes what you have stated is true but you have taken my statements to extremes, of course there is always direct and reflected sound and if the timing is less than 30 milliseconds then the reflected sound is perceived as part of the direct sound, but unless you are listening to your system in a shoebox then the brain’s sound arbitrator can distinguish and dismiss the reflection. For most of us the room acoustical parameters are what they are and we don’t use DSP to counter them. As a matter of fact, in my systems I take the room’s acoustic parameters as a given, along with everything else, and it is only then that I start to adjust the resultant sound at the listening chair position to match my target sound qualities. I simply don’t worry about many, if any, of the individual contributors that I can’t control and focus solely on adjusting the composite resultant sound at the listening chair position.
You got me curious now. Please post some audio recordings of your system so that we can hear what all that working knowledge on spatial audio and psychoacoustics has been able to do for you and the sound of your system. Let’s hear what you have been able to accomplish. Surely all this information has yielded something special. Please share some pictures of your system and room set up, along with some audio recordings. I’m looking forward to hearing what has been distilled from all the information you have presented here.

