Please be assured and to resolve "Sound" issue kindly follow the given below steps:
1. Disconnect all accessories and remove any third-party case form your phone.
2. Check device in safe mode: Press and hold the Power key, when Power off icon appears >Press and hold the power off icon. Exit safe mode: Hold the power button and select restart on the device.
If the issue still persist, kindly register your concern in Samsung Members app (Samsung Members app > Get help > Feedback > Error report/ask question). Note: Please send device log files within 15 minutes of issue occurrence along with the exact issue details.
