no sound when using airplay and apple tv

Hello there redmncivic,

If you are still unable to get audio when playing your content from your Mac via AirPlay to your Apple TV, and you have already restarted your Mac, I would use these troubleshooting steps specifically to help isolate and resolve the issue.

Apple TV (2nd and 3rd generation): Troubleshooting audio issues

Restart your Apple TV by holding down Menu and Down on the Apple Remote for six seconds. The Apple TV may take a few minutes to restart.

If you're using a home theater receiver or optical digital audio port (sometimes called S/PDIF or TOSLINK):

1. Connect your TV directly to your Apple TV with an HDMI cable.
2. If the audio issue isn't resolved, see the manufacturer's user guide for additional support or follow the steps below.

If you continue to experience the issue after completing the above steps, try these steps:

1. Set the audio output mode for the Apple TV:
   1. With your Apple Remote, select Settings > Audio & Video.
   2. Change the Audio Output setting from Auto to 16 bit.
2. Turn off the Dolby Digital Out setting (your TV or receiver may not be properly detecting a Dolby Digital signal):
   1. With your Apple Remote, select Settings > Audio & Video.
   2. Change the Dolby Digital Out setting from On to Off.

Thank you for using Apple Support Communities.

Regards,

Sterling

help , I have done everything you said and no sound at all . The 1st time I used Apple tv it was fine but this 2 nd time no joy.