iOS 6 beta 3 has revealed that you can send audio from the Apple TV to AirPlay-enabled speaker systems.
Apple’s latest beta release for Apple TV will detect AirPlay-enabled speaker systems connected to the same wireless network, and then you can choose from the detected devices for audio output. This means you can watch a movie on your HDTV and broadcast the sound to your AirPlay enabled speaker systems.
AirPlay doesn’t support 5.1 surround sound, so as of right now, you won’t be able to enjoy your surround sound wireless.
iOS 6 is expected to be released to the public this Fall. We will keep you updated on new Apple TV features as they become available.