Strange noise coming from the front

[PoloCP06]

I have a 2006 1.4 TDI polo, it's been spot on for 4000 miles but all of a sudden it's developed a bussing type noise from the front somewhere, it gets hight pitched the faster I go, on idle it sound normal but after around 30mph the noise starts and by 60 it's decently loud, its hard dto describe but it's like something rubbing but I have had the under tray off looked at all the belts and everything looks in good order. Any ideas?