In all string instruments, the sound is radiated as a result of the coupling of the strings with a plate. In the case of the piano the energy given by the hammer to the string, flows through the bridge to the soundboard which dissipates it into internal losses and sound power. Thus the soundboard acts like a mecano-acoustic transducer. In this study a modal analysis is used in order to investigate the vibration characteristics of an upright piano soundboard. The results of this a
nalysis are used for computing the radiation characteristics of the soundboard. Finally a way to improve the radiation efficiency of the soundboard in the low frequencies is proposed.