Sound radiation of piano soundboards, measurements and modelling approaches Seminar

In pianos the soundboard has the key role of converting string vibration into sound. Soundboards are normally made of a wooden board with a set of reinforcing ribs on one side and bridges on the other one. The bridges provide the connection with the strings while the ribs serve to reinforce the board to sustain the vertical load of the strings. In addition, the manufacturing procedure is designed to leave a residual curvature, which supports the string load, and the board itself is often tapered to the edges. Alongside with the type of wood, all these features have a potential important effect on the sound radiation properties of the finished instrument.

This talk summarises acoustic and vibration measurements performed on two different soundboards. These differ for the type of wood, laminated vs tone-wood, and for the manufacturing procedure: the first one is glued on a back post assembly which is itself curved and this gives tension and a crown on the board; the second one is heated and while hot and shrunk is glued to the back post assembly, as the soundboard reaches room temperature it expands thus producing the crown.

A modelling numerical approach to assess soundboard acoustic and structural properties will also be introduced.