Kenwood Car stereo receiver

Question

Just installed a new kenwood receiver KDC-x492 to replace another that i thought was bad. The old one worked fine until it just wouldnt work right anymore. The volume was real faint and you could'nt turn it up, no bass or tone at all. THe speakers that I'm using are a fairly new set of Rockford -Fosgates 6x9's that worked well until this problem occured. The new one that I put in is doing the same thing With the speakers being the common denominator. + and - are hooked up properly and I'm sure my wiring is correct.I've disconnected 1 speaker at a time and no change. What could be wrong? Need some help. Thanks