KEYBOARD INSTRUMENT

PROBLEM TO BE SOLVED: To make responsiveness with a high frequency satisfactory while validly obtaining a driving force for exciting a soundboard in the case of using a voice coil type excitation part for the excitation of the soundboard.SOLUTION: A grand piano is configured such that performance information is output in accordance with the operation of a key in a muting mode, and that a driving signal showing a sound based on the performance information is output to an excitation part installed in a soundboard 7. The excitation part includes a voice coil 512 to which the driving signal is input. The length of the voice coil 512 is equal to or less than the total of the magnetic path width of a magnetic path space 525 and length which is two times maximum displacement sw of a vibration part in a state that it is connected to the soundboard 7. The length of the voice coil 512 is determined as mentioned above so that it is possible to make responsiveness with a high frequency satisfactory while validly obtaining a driving force for exciting the soundboard 7.