I have a gypsy guitar made by Douglas Foster from Brisbane, Austrslia. He was a hobby luthier but he made some beautiful instruments and this is one. It has a D hole with a resonator, so it does rhythm and lead both very well. It has a spruce top and black walnut back and sides. Anyway, I am getting some buzz out of the tailpiece on the middle strings. I corrected this with a piece of cardboard coaster years ago, but it's starting to buzz again. I can place more cardboard in between the tailpiece and the spruce front but I am looking for advice on the proper way to address this. I don't want to dampen any sound coming of the front.