Get rid of the chat window in Premium articles;
If i open 5 articles from premium authors, chat window is opened on all them and sound is annoying (make the sound mute by default) or removing chat which is a better solution. If anyone wants to chat, one can open a separate window for chatting.
If you mute the chat in the upper right corner it will remember your setting on all future windows/tabs you open. If you are subscribed to multiple services, the mute doesn't carry over from service to service - you have to adjust volume once per service as users may want to get a ping on one service and not another at a given time.
You can also minimize the chat window next to the sound button - though this is required in each window/tab you have open. Many users have indicated that they prefer to have chat open in all their windows by default so 'they don't miss anything'.
Hope this helps.