Why does the sound go off in the middle of a cd?

Apple TV doesn't play CD's. Can you provide more info on the issue?

It's best to keep everything in one thread.

Intermittent issues will typically be caused by interference. If on wifi try Ethernet. Make sure router is up to date. Reboot ATV and router.

You can go to istumbler or netstumbler to get a report of the network, look for signal strength and noise