If it is making the noise at all speeds have some one else drive the car at a slow speed and you walk beside it. This will allow you to at least figure out where it is coming from. Then jack it up and take a look.
The tough part of this is having some one else drive your car while you walk beside.
Good luck in locating the noise and let us know what you find out.
I had this on a little S-10 pickup, it was a u-joint...had worn a hole in the side of the cap. Guess I caught it just in time. I never did like those cheby joints because I can't grease them, at least until they are changed out...good luck.