ive been searching and looking for info on this but cant narrow it down to the one i want,

im looking for an am to run my 12inch sub BUT would like it to run both of my 6x9 aswell, just because i dont want to run my 6x9 of the headunit??

 

all depends on the impedance of the sub. Most 4ch amps will run in tri-mode allowing you to bridge channels 1 and 2 to run a sub and channels 3 and 4 separate to run left and right. Also if it's a dual coil sub then you don't need to bridge anything