'89 Jetta

What is the most likely to be causing a roaring noise in the left front of my Jetta? It makes the noise from 20 mph on up, disengauging the clutch while driving has no effect on the noise just vehicle speed does, faster means louder. I'm not a FWD guy. What should I check for?
Les

On my old honda, the driver side axle was broke and made the car vibrate at speeds above 30MPH. Slip the rubber boot back and check to see if its still one part.