Start by checking your audio multi-output settings.
1. From the PlayStation Main Menu access the Settings menu.
2. Scroll down and select Sound Settings.
3. Select Audio Multi-Output (this is used for running audio through multiple connecters like a headset or sound system and can downscale the audio).
4. Try setting this to Off.
If you continue to have trouble, please try resetting your audio settings with the steps below.
1. From the PlayStation Main Menu access the Settings menu
2. Scroll down and select Sound Settings
3. Select Audio Output Settings
4. Select your connector from the list
5. Select Automatic on the following screen
6. Follow the remaining steps. Leave everything on default and continue by pressing X.