| 摘要 |
PURPOSE: To perform acoustic generation like a natural musical instrument by utilizing the resonance vibration of a lower front board. CONSTITUTION: The output of an electronic piano is supplied through a lead wire 20 for electric signals to a voice coil 15. Thus; by audible frequency electric signals supplied to the coil 15 for forming one of electromagnetic drive units, attracting and repulsive force corresponding to the height of a frequency and the strength of the signals is generated between a yoke 18 and a pole piece 19 at the tip of a magnet 17 for forming the other electromagnetic drive unit. A magnet system composed of the magnet 17, the yoke 18 and the piece 19 is fixed to the supporter 14 of a back board 13 and is constituted as a moving- coil type. Thus, the attraction and repulsion generated between the electromagnetic units becomes driving force for vibrating the lower front board 12. By considering the characteristics of the lower front board 12 in this case, acoustic output similar to the output from a natural musical instrument is obtained. |
