Aural alert for private message is not very noticeable

[jonaseberle]

I find contact me's pretty easy to miss.

I believe it is this sound that gets played for a private message by a controller:

https://github.com/xpilot-project/xpilot/blob/master/client/Resources/Sounds/PrivateMessage.wav

Could we make that a more "alert"?

[justinshannon]

Do you have any suggestions for a better sound?