The A6 has a 3db down point of 55 Hz and the A3 is 50 Hz. I would just set them at 80 Hz and let the sub handle the rest of the work. You can experiment setting them to the values that I mentioned and see what sounds better to you. If you set them both to large or full range, the receiver will be doing more work by trying to reproduce the low frequencies for fronts and center.
Actually, the Audyssey setup placed it on 80Hz and Small speakers.
I tried lowering to 60 Hz Crossover, but the 80Hz Crossover sounded better.
Sub is connected via RCA->LFE and knob is set to LFE mode. It's a PSW110 btw.
So setting it to Large makes the Amp work harder and consume more power? Tama ba?
Then small na lang.. lower electricity consumption.. Hahahaha..