You might find this small piece of trivia interesting. While I was looking at the different voices for Garmin, I came across an article that links to this page. Looks like this singer is the real Karen who provided the Australian Female voice for Garmin. Link for the article itself is also in the news section of her website.
http://www.karenjacobsen.com/karenjacobsen.html
http://www.karenjacobsen.com/karenjacobsen.html