Regarding the discussion about the sound choice, I'll say what I've said time and time again: Anything that is not constructive is in vain. Opinions on particular sounds are more subjective than on Jarrod's toe socks, so to change a notification sound, you have to a) offer an alternative, not just "the current one is bad, give us another one", and b) there has to be reasonable agreement that the new choice isn't worse than the old one. In such a case, we're happy to change notification sounds. The sounds for the no-longer-existing sites are still there, so you even have some suggestions to start with (1, 2, 3, 4).
Also note that (currently) the sound is identical per chat site, so all rooms on chat.stackoverflow.com have the same sound, and all rooms on chat.stackexchange.com (which includes the AU rooms) have the same sound.