crossover settings
Most people set the crossover frequncy to 60 or 80. I set mine to 80 and can tell little diffreance between the two settings.
If your using the sub pre-out from your reciever turn the LFE switch to on.
If your using the high level speaker outputs, turn the LFE switch to off.
Crossover frequncy settings depend alot on what type of speakers you use.
I have Axiom M60s which are a "full range" tower speaker that I set to small for H/T and then set to large for tunes all at a crossover of 80 on a HSU VTF3 Mk-II sub. This works well for me, but play around with it a little bit, and set the crossover and speaker size to what sounds good TO YOU.
Everyone hears a little different, and everyone has different tastes.
I'm sure you'll get other opinions on this.
Hope this helps