I just recently installed a new aftermarket stereo and all the speakers work except the mids in my doors. Does anyone know why ?

 

did you have mach 460?

 

Yes I have the Mach 460 system

 

well I'd first check to see if the wires are connected to the speakers... perhaps the speakers are blown? without having a picture of the speaker(s) that you are referring to I really can't make a good determination as to what's going on.