Whatever a certain speaker is set too, any bass below that xover number is diverted to the sub/LFE channel. So anything below 120 on the fronts goes to the sub, and anything below 90 on the center goes to the sub. This will cause some directionality in the bass, but its better than making ceiling speakers try and play 80hz I bet
And you generally wanna set your sub to 120hz, because the LFE channel can go that high. I dont agree with setting all speakers at 80 including the sub if you can, because you may miss 80-120 in the LFE channel.
On my HSU, I have it's on board xover set to OUT, which is bypassed, and the marantz xover set to 120hz for LFE. Since my klipsch are large, I have the center and fronts all set at 80hz in Audyssey.
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