After removing the old soundboard and cleaning all the old glue off the mortises, Its time to fit the ribs. In this piano, we selected sugar pine in the bass end of the piano for flexibility and Spruce ribs in the treble to drive the higher frequencies. The ribs are then cut to support the crown of the soundboard and fitted to the piano. A flatter radii is used in the bass to promote flexibility and progresses to tighter radii as the ribs reach the treble. To recap, everything selected here is to promote flexibility in the bass and stiffness in the treble. The soundboard panel is roughly cut, using the old panel as a guide. Then, the panel is fitted to the case of the piano. Once that is achieved, the long side of the soundboard to around the nose is diaphramed. (tapered thinning on the the outside edge) This again, helps promote more flexibility in the bass. The panel is placed in the piano and the rib positions are marked.