A specific type of a human operator's gesture (such as a downward, upward or lateral swinging movement) and its movement amount (such as a speed or acceleration of the movement) is detected by a movement detector. The detected movement amount is compensated in accordance with the detected movement type, and various factors to control dynamics of a music performance (such as tone volume, color, pitch, effect etc.) are variably controlled on the basis of the compensated movement amount. At least one of minimal and maximal values indicative of the operator's repetitive gesture is selectively extracted from the output of the movement detector so that the performance tempo is controlled on the basis of a particular time point at which the selected minimal or maximal value has been extracted. Extreme value (minimal or maximal value) indicative of the operator's repetitive gesture is extracted from the output of the movement detector and a tempo controlling point is set a predetermined time after a particular time point at which the extreme value has been extracted, so that the performance tempo is controlled on the basis of the thus-set tempo controlling point.
Apparatus and method for controlling performance dynamics and tempo in response to player's gesture