A cleat would be glued on the underside of the soundboard to stabilize the crack and keep it from spreading. You might be able to see it with a mirror, but otherwise I suggest you loosen the strings enough to be able to get your fingers into the body...
A cleat would be glued on the underside of the soundboard to stabilize the crack and keep it from spreading. You might be able to see it with a mirror, but otherwise I suggest you loosen the strings enough to be able to get your fingers into the body...