I wonder if Tesla implements this patent in the model S? Automated Audio Optimization System - Patent application sounds pretty cool. "An audio system is provided, as well as a method of using same, which utilizes a plurality of sensors integrated into the vehicle's seats to determine which of the seats are occupied. The system selects a pre-defined optimum acoustic sweet spot from a plurality of stored acoustic sweet spots based on which seats are occupied and based on a set of acoustic optimization configuration instructions. The system automatically adjusts the left-right speaker balance controller and the front-rear speaker fade controller to the specific left-right speaker balance setting and the specific front-rear speaker fader setting defined by the optimum acoustic sweet spot. The acoustic optimization configuration instructions, which define the optimum acoustic sweet spot for each combination of occupied vehicle seats, may be stored in the system's memory by a vehicle manufacturer, third party, or end user." Read more: Automated Audio Optimization System - Patent application As I've never seen the front/back left/right speaker balance change other than my settings, I'm assuming this is not implemented. However, this can easily be controlled via software. I wonder if it'll be part of v6? I know they can detect people sitting in front driver and passenger seats. But are there sensors for the rear seats too ?