Cancer
06:46 Apr 23 2017
I think this has been fixed. This feature is browser dependent. I can confirm it's working on Chrome and Firefox. Results with other browsers may vary.
There is also a new feature where you can now upload mp3 files (so long as they're under the size limit). The old system only allowed wav files. In either case, you'd want to upload a short, 1-3 second clip. Anything else would be pretty annoying.
Also make sure you upload a file AND check your notification setting (set it to play or always play). Some members upload a file, but they have their notification setting to "never play", so they never hear anything.
Unfortunately you cannot test this feature on yourself. The reason is, when you load the Message Center, the notification sound doesn't play. When you send yourself a message, you're immediately bounced to the Message Center. So you don't hear anything.
In the past you could bite yourself to test it, but that doesn't work anymore either. I added a funny error message for when you bite yourself.
So to test, someone else needs to send you a message. You can always sign up a new account here on the test server to.... Test.