I have an enclosure with 2 JackHammer 45's in it, I am going to power it with a Crunch 1000.2 2-Channel Amp, however my subs are at 2-ohms and my amp bridged will run at 4-ohms, so can i just use one channel and leave the other channel open, or will this damage my amp?
You can run them off of one channel but I wouldn't recommend it. Doing that you'll only be putting out 250 watts if your lucky. If you can I would try and sell that amp and purchase a class d mono block that does around 500 watts rms @ 2 ohm.