Hello Mark,
Thank you for contacting Microsoft Community Support.
I'm sorry for any inconvenience you're experiencing. Here are some steps you can follow and try to resolve your issue:
1. Check HDMI Connection: Unplug and re-plug the HDMI cable between your PS5 and Planar monitor. Try a different HDMI port on the monitor (if available). If possible, test with another HDMI cable to rule out a faulty one.
2. Verify PS5 Audio Settings: Please go to Settings > Sound > Audio Output then set Output Device to HDMI and then please change Audio Format (Priority) to Bitstream (DTS or Dolby Digital).
3. Check Monitor Audio Settings: Some monitors have built-in speakers but require audio settings adjustments. Open the monitor’s menu and look for audio settings. Ensure volume is up and mute is off.
4. Use External Speakers or Headphones: If your monitor doesn’t have built-in speakers, you’ll need an external audio solution. Plug headphones or speakers into the PS5 controller. Alternatively, connect external speakers via the monitor’s audio output (if available).
5. Restart Everything: Turn off your PS5 and monitor and unplug them for 30 seconds then please plug them back in and turn them on.
6. Update PS5 System Software: Go to Settings → System → System Software Update. Install any pending updates.
7. Try a Different Audio Output: If HDMI audio isn’t working, use an optical audio adapter or USB sound card. Some users have had success with HDMI audio extractors.
I hope these steps may help you to resolve your issue.
If none of these step works, please contact to Microsoft Live Support Team via Contact Us - Microsoft Support Best Regards,Thomas | Microsoft Community Support Specialist