Often, after installing a dimmer switch, or replacing bulbs controlled by a dimmer, you'll start hearing buzzing or humming from the bulb. As far as the bulbs are concerned, a bulb consists of a series of supports and a fine filament of wire. When you run current through a coil, it becomes a magnet. With the metal constructed light fixture, the filament will move or vibrate at a fast speed. This is what causes the singing. You can try replacing the bulb with a "rough service" type bulb. They're usually much stronger and better supported. Chances are, however, that switching bulbs won't make that much of a difference. Perhaps the buzzing will go away at some dimmer settings, but not at all.