I use mine Input Y, Limiter ON, HPF@50hz.
50hz is the lowest freq for HPF I'd rather just a smudge lower but most cabs arn't that great below about 50hz anyway. I don't seem to lose much low end, seems to just tighten it up a bit, and I know my cabs arn't working too hard.
Channel A sees an 8ohm load in the form of a Carvin LS1503 3-way PA cab. I have bridged into this cab(1050w) but that is a little much and the cab works really hard(but man is it loud!)
Channel B sees another 8 ohm load in the form of a no-name 18" sub.
I stack the two cabs so I can get the 6" and tweet of the LS1503 closer to my ears, Then dial in the 18" till it just fills out the sound.
I bridged the XLS2000 into both cabs once (>2000w) fried my 15" and the 6"

I like that running a pre- poweamp setup allows you to use any combination of cabs.
Remember that watts alone don't equal volume, watts+speaker area = volume. If you don't get enough volume out of one cab, Bridging will drive it harder(and closer to it's limits) and give you a lil more volume but adding another cab fills out the sound alot more than bridging a single(cab).
Have fun with your new amp, I'm lovinng mine!
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