stereo or mono?

I have a 2 channel amp running two 4 ohm subs which is fine and all but there is a switch on the amp which can select between low pass mono, full range mono and full range stereo. Can I run a sub off each channel and have the switch on low pass mono so i can utilise the low pass crossover frequency control? Currently im playing it safe and have the switch set on full range stereo but i dont really want to waste power by trying to get the subs to play frequencies beyond thier range.

yes you can, normally the amp will take either the left input and put that on both outputs, or it'll sum the 2 inputs and put that on both outputs. Either way you'll get a mono signal going to the subs and you can use the lowpass.

Does it matter if the subs are in a parallel wiring configuration (so the amp is seeing 2 ohms)? Some amps (like mine) will only do mono bridged output at 4 or 8 Ohms. 85GSi, you'll have to check your amp's spec's to see if it's possible.

Another wiring question: can you run a wire from each channel on the amp to each channel on the subs (so each sub is getting both left and right output)? I'd think that would only be a problem if you were sending a stereo signal to each channel on the amp.

Another wiring question: can you run a wire from each channel on the amp to each channel on the subs (so each sub is getting both left and right output)? I'd think that would only be a problem if you were sending a stereo signal to each channel on the amp.

you mean wire the + and - from both channels to the + and - on the sub?

if so that's a VERY bad idea, you'll actually be wiring the channels in parallel and any difference in their signal will effectively create a short circuit in the amp. Actually, with bridgeable amps, you'd create a short circuit even without a difference in the signal because of the way they're set up. Extremely bad idea, the only amps I'm away of that can do this are the new JBL/Crown amps, and that's only because they specifically designed them to be able to do that.

that's what I was worried about... good thing I never tried this out :)