How to create an audible signal for thread updates?

I spend a lot of time playing M:tG on a game forum very similar to this one - http://rpol.net . I'm trying to find a way of letting me know audibly that one of my games has a new post, so that I don't have to keep getting up and going over to my computer, interrupting whatever I was doing.

I typically use Firefox 7.01 - I don't like updating Firefox until most of the add-ons which I use are updated for the new version. But I have recent versions of Google Chrome and Apple Safari as backup browsers. I have set my game tabs to update every five minutes using the Tab Mix Plus add-on for Firefox. But I don't want to get up every five minutes to check.

I've looked through the Firefox add-ons, but can't find any help. I've been unable to deduce the right search terms to have Google find what I'm looking for. And I'm hoping there is a free/freeware solution to this.

Thanks in advance for your time,

Jeffrey G

 

check out this addon see if it is more to your needs
https://addons.mozilla.org/en-US/firefox/addon/check4change/