I've got Poweramp trial currently installed in my car's android 4.4 head unit and it sounds great.
The actual problem I'm trying to solve is to have the ability to fade to the rear speakers. After reading the fourms I believe if I can disable DVC "Direct volume control" my head unit's speaker balance and fade control will take over and I can achieve what I want to do. ( fade slightly to the rear )
The problem I'm having is I'm unable to locate
Poweramp SETTINGS -> AUDIO ENGINE