Q: Why doesn’t the Apple TV device allow me to play music on my stereo instead of just through my TV, or does it?
A: As is evident in the name of the product, Apple’s clearly been focusing its marketing for the Apple TV toward its video capabilities, but there’s absolutely no technical reason why the Apple TV cannot be connected to a stereo system.
The Apple TV includes HDMI, component video, RCA audio, and digital optical audio (TOSLINK) output ports. Any of these can be connected to many modern television sets, sure, but the RCA audio connections can interface with even the most rudimentary stereo and home theater audio setups. If you have a more feature-rich audio receiver, you may be able to use the optical audio port. HDMI is also an option, if your A/V receiver supports it.
It remains to be seen whether the Apple TV will simultaneously utilize all of these output ports, or whether you’ll need to select a setup ahead of time, but even in the worst case scenario, you should be able to find a way to get an audio signal to your stereo.