the noise is being caused by the resonant vibration from the engine at a certain rev speed,..
the engine at 3000 makes it most "activity" at that range, it can also be noticed in the exhaust note.
pressing in on the cluch will eliminaté the noise as the chassis is disconnected from the engine when you press in the clutch,
if you can, take the cover off the underside of the steering column cowling
then see if its associated with the wiring arrangement under there
