Tone control apparatus and method using virtual damper position

Virtual damper position data, simulatively representing a position of a damper member provided for suppressing vibration of a string in a physical tone generating mechanism of the acoustic piano, is generated on the basis of key-on data, key-off data, released key position data, damper pedal position data, sostenute pedal-on data and sostenute pedal-off data. Release characteristic of a tone signal to be generated is controlled on the basis of the virtual damper position data. When the sostenute pedal-on data or key-on data has been supplied, the virtual damper position data is set at a value corresponding to a maximum damper release position. Virtual damper position data is variably generated on the basis of at least one of the released key position data, damper pedal position data supplied after the supply of the sostenute pedal-off data or key-off data.