Your Surface may have Omnisonic speakers that create an immersive experience when you take calls or watch movies. With Dolby Audio Premium(TM) processing, get the best sound from your device. Here's how to change some basic sound settings:
Go to Start > Settings > System > Sound. In Output, select Device properties.
Dolby Audio is on by default. You can change the default volume, sound effects, and the speaker configuration. Here's how:
Select Start , enter Realtek Audio Control, and select the app.
In Playback devices, select Speakers.
If you don't have the app on your Surface, download it from http://aka.ms/RealtekAudio.