An object of the present invention is to provide a hard disk drive or related apparatus in which a possibility of head crash can be reduced to minimum even if the apparatus receives an external impact during the operating state. In this patent application a systematic methodology is presented for active modal equalization able to correct the modal decay behaviour of a loudspeaker-room system. A pitch length fixing unit 3 makes the voice signal have a constant time length of a section corresponding to a unit pitch, and generates pitch waveform data.