[Vwdiesel] buzzing

[Rudy]

I have a vibration (buzzing) at a certain low rpm, I hear or feel it in
every gear as I accelerate up thru the gears.  I just changed the timing
belt and tensioned.  It did it before I changed belts and is much less
pronounced now, also changed all 4 Motor Mounts along with the belt.
 
I've read/heard that if the timing belt is too loose or tight it'll do this
but can't remember which, (loose or tight)
 
Anybody have any thoughts or experiences with this they could share?  Thank.
 
Rudy