Yams provide default support for Audio setup. which means we do not provide audio support for custom audio support or laptop to TV connection. 

If you see a red mute icon in Kodi at the top right corner please press the F8 button to unmute or click on Plus button on your keyboard
eventual when a movie is playing go to audio settings and then increase the volume using remote. 

For members with ouya box please ensure you have SPMC installed and not XBMC/Kodi. as the default XBMC/Kodi version from ouya store does not have audio license. 

Further for those that hook their laptop upto the TV can take a look at this video guide on how make the audio work: https://www.youtube.com/watch?v=e57b0H01sOE