1. Do you hear the beeps and bonks for the user interface?
No
2. What is your setting in Settings > Audio & Video > Dolby Digital?
Auto
3. Does changing that setting have any effect?
No
4. Is your Apple TV plugged via HDMI directly into a TV?
No
4b. If not, what is the manufacturer and model of the device the Apple TV is connected to via HDMI?
Marantz SR-7001 AV-Receiver
I have the Apple TV connected to the AV receiver using HDMI and to a DAC using TOSLINK There is an analog connection from the DAC to the receiver (obviously). When I try to play music through the DAC, it stays silent, when I switch to the HDMI connection to works. Once I haved switched to the HDMI connection, I can switch back to the analog connection, and also get music there. The optical out works until the ATV gets into sleep mode and wakes up again.