Audio Systems: poss. amp problem, voice coils, subwoofer amp

Question
radio sounds on highs only in front doors ,no rear sound , no bass at all

Answer
I need more information;  make and model of all the equipment and the car/vehicle mounted in.

But, if you have external amps for speakers then check the back amp which may also be the subwoofer amp.  In this case it involves checking all the amps (and speaker wires for shorts, etc. )

Also, in econo systems this is generally a condition where the voice coils in the speakers have been overpowered and are either open or loose on the coil form.  In this case its repair involves replacing the speaker.

Let me know more so I can give you information relating to your installation and vehicle.