Vlaams-Brabant, and to be very specific, Zennevallei, so the Southern stretch of Flanders squeezed in between Brussels and Wallonia.

People from places like Beersel, Halle, Sint-Pieters-Leeuw, etc., tend to be speak the way news anchors do. Of course, they have their local dialects too, especially the elderly, but in general, they speak a very clear Standard Flemish which almost sounds artificial.

Look at a guy like Koen Wauters for example. He's from a working class background, but grew up in the Zennevallei, and speaks a pretty clean Standard Flemish compared to Tom Waes. That's not because he's faking it. It's the normal accent from that area.