CreateSound stopping after a few seconds

[Semajnad]

I have the below code, and the sound plays, but only for about 3-10 seconds then stops. Any input as to why this is happening? EG. If I save the file ( so it auto-reloads) the sound starts playing, when I alt tab to the game it stops. If I just save the file then dont' touch anything, it seems to play fine?

function GAME.PlayBackgroundMusic( path )
    local sound = CreateSound( game.GetWorld(), path )
    sound:SetSoundLevel(0)
    sound:Play()
end
GAME.PlayBackgroundMusic( "music/background.mp3" )

Thanks.

Ideally I just want to achieve repeating background music - what's the best way to do this / make sure when the music ends it starts playing again.