Sometimes when I play fairly hard I am getting a faint buzzing sound. Its not coming from the string/fingerboard, and its not very loud, but it gets picked up by microphones. If I hold onto my bridge it goes away. Is it the bridge itself vibrating, or is holding it just preventing the vibrations from reaching the body and actually vibrating the endpin? (i have bridge adjusters if that matters) Anything I can try to remedy it? Thanks.