starting subwoofer integration up in the mid bass is fine for Home Theatre, but if you are chasing ultimate high fidelity coherence the odds of slapping together disparate pieces from different manufacturers and getting complete integration through the mid bass will be very challenging. this is where most/all the music lives.
OTOH getting reasonable coherence in deep bass integration is more doable. you need a main speaker to use it's designed in integration above 50hz if possible. and then mess with the transition underneath that frequency. missing it a little down there will be much less frequently an issue unless you listen at high SPL's typically......then there is no escaping it.
as far as class D for deep bass; stay away from absolutes. if it sounds better then it is, if it does not then it's not. but there are so many variables to consider that insisting on A/B for deep bass will simply get in the way of success. if you take the signal from the main amplifier (ideal) then class D has clear advantages. if the deep bass signal is coming from an outboard crossover or preamp then I see the matching A/B amp relevance, but then the weakness (or character) of that outboard crossover (none are perfect) gets subtracted from any advantage of the matching amplifier. pick your poison. this is why people buy fully integrated full range speaker systems.
Thank you, Mike. I understand on all points. I agree with your concern about starting subwoofer integration up in the mid-bass, and I agree with staying away from absolutes. I, too, would much prefer a fully-integrated full range speaker system. Unfortunately, it does not seem that ML will be producing exactly what I would want anytime soon.
The 15" driver likely is the weakest part of the Neolith design, because it is being asked to do too much. The task of that sole 15" driver should be broken out and handled by a separate
tower of 15" drivers. I am just brainstorming to try to figure out a way to accomplish that by dropping the internal 15" cone -8dB and grafting on the subwoofer towers.
I agree it would be a much more conventional solution if I were to use the Thors or a stack of the future MartinLogan BalancedForce 215s simply to supplement the Neolith from 50 Hz down.