Hi Robert,
Nice comments on your Axiom speakers. Tweaking the setup of all the main speakers always pays off in sonic dividends.
As to your comments about the JBLs, I think you're confusing the old boomy JBL sound with smooth linear bass extension, which characterizes Axiom's speaker design. Brands like JBL used to add a big hump in the 60 Hz to 500-Hz range, which gave the subjective impression that the speaker had impressive bass output, even if it didn't go all that deep.
In the '60s and '70s that JBL sound came to be known as the "West Coast sound" (kind of thumpy boomy disco-like bass with exaggerated upper treble). Bass coloration like that can be fun at a party but it lends a fat, bloated character to male vocals and some instruments. Modern JBLs tend to be somewhat smoother in the bass.
You will find other threads on this forum about loudspeaker "break-in" but what acutally takes place is a psycho-acoustic "break-in" wherein your ears and brain are accommodating the sound of new sound reproducers in your particular room. Actual loudspeaker measurements and double-blind listening tests in which I've participated show no actual changes whatsoever in the loudspeaker frequency response or the rankings of the speakers by listeners over some years. Any mechanical/acoustical break-in occurs within a few minutes (or less) of powering up the system.
Regards,
