I am having issues with a particular customer network. We can open OWA 2013 in Chrome and notification sounds work just fine. In IE 8 through 10 however the notification pops up but there is no sound.
We can also open OWA 2010 from another server and the notification sounds play just fine there too.
I have tried adding it to the trusted sites as well as looking for GPO's that may be affecting this functionality but I cannot find any.