I wanna run 4 speakers of an amp. They can handle each can handle 100 rms. So do I actually need a 4 channel or will using a 2 channel work, just wire it 2 left and 2 right?
Depends on the application. Are these subs? If so what are their impedances(like 4 ohm etc)? Technically you only need ONE channel to run a set of subwoofers.