Regarding the sound notification in Marketplace chat, the way it now works is that if the chat window is the active/visible tab on your screen, it won't make a sound. Also, it only makes a sound for mentions (i.e. @your.name @all or @here or a direct message).
Many subscribers have requested we add an option to get a sound notification for every message. We will be adding this very soon.
This feature is now available. Instructions on how to enable can be found here:https://seekingalpha.com/feedback?uri=/topics/724-how-can-i-get-an-audio-notification-for-every-chat-message/
Customer support service by UserEcho