The buzzing sound could be coming from a variety of places and can be very irritating. The most common place is from the fingerboard. If the nut on the pegbox is too low or the grooves are worn or if the fingerboard has not been properly set up and planed, the vibrating strings will buzz as they make contact with the fingerboard A new nut properly cut and fitted, or a new fingerboard will quickly fix the problem. Another reason for a buzz could be because one of the seams of the instrument has come unglued. This is a more likely to happen on older instruments and will require gluing the seam back together.