So your suggestion is to change speakers and or electronics. It’s never going to happen. I can tell you that over those 3 years Marty was here in 3 separate occasions and each time we tried over and over to dial in the subs. When we thought it sounded good we discovered the sub master volume control was virtually off. Marty is never a quitter but I believe he too felt it was an exercise in futility
Where am I am suggesting you to change anything? You have a great system that you enjoy and surely sounds great.
I am just analyzing your and Marty findings and trying to correlate them with some technical aspects. We have now found many reasons why you should NOT have subs!