>>The speaker-level connection would rely on the often inaccurate internal sub crossover for the bass management to the sub and there wouldn't be any to the mains unless there was a fixed high-pass filter on the sub's speaker- level outputs.

D'oh !!

I forgot about that. Whatever would I do without JohnK ?

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8