Some sound bar models feature a Night Mode setting which, when activated, will improve the clarity of dialogues by adjusting some sound settings. This allows you to hear dialogues clearly even at low volume levels.
The feature is designed to give the user an option to enjoy content at low volume levels. This helps to prevent the risk of excessive noise levels - especially from the Subwoofer - in certain circumstances (typically at night, etc.).
Night Mode can be activated or cancelled using the "NIGHT" button on the remote control (number 16 on the below image).
If you're experiencing unintended sound effects while playing content, or feel like your Subwoofer isn't working properly, try pressing the NIGHT button on your remote control. Night Mode might have been activated unintentionally and could be the reason why the sounds seem different.