Experimental investigation of the effects of extra mass on a piano soundboard’s vibration property

A soundboard, as an important resonance component of a piano has been continuously studied in the past several decades. It is known that the variation of mass distribution on a soundboard could affect its vibration properties and the sound quality of a piano. However, those effects have been seldom investigated until now. In this paper, an experiment is carried out to study the effects of additional mass‐blocks on a soundboard. Small pieces of metal blocks are pasted on several different locations on a soundboard, and a laser vibrometer is used to extract its mode shapes and spectrum under the excitation of an acoustic source with frequency ranges from 10 Hz to 1 kHz. The results show a notable difference of spectrum between mass‐added cases and original in low frequencies, but little difference in high frequencies. It could be concluded that additional mass‐block could greatly affect the energy of the low‐mode of a soundboard.