Thunderbird, how to change incoming mail sound?

[LeandrodaFL]

Everytime I get a new email, Thunderbird makes a beeping sound, just like the application Mail. However, the Thunderbird sound is a really bad beeping sound, the same one you here when something wrong happens when using your Mac. The sound from Mail is like a doorbell, really pleasent.

So, how do I change the Thunderbird sound, is it possible?

 

[Weaselboy]

Does this help?

 

[LeandrodaFL]

Does this help?

Thanks. Out of curiosity, wich sound is at 1:41, and how do I get it in .wav? Thats a sound I would like to use.

http://www.youtube.com/watch?v=qHO8l-Bd1O4

The video is a Steve/Bill cartoon, I bet most here have seen it.