I have read all the posts I can find about the humming noise and I still have to ask this question.... My MH ballast hums about as loud as a wore out pair of hair clippers. It is louder than my fans and I can hear it through the closed door. Is this normal? I recall certain streetlights or security lights that make some noise louder than others before they burn out. I realize that now it seems louder than normal because it is in a inclosed area and not 15 or 20 feet above my head. How loud are they supposed to be? I know thats tough to answer but any info will help.