Sound synthesis system having pitch adjusting function by correcting

Abstract

A sound synthesis system, having a pitch adjusting function, comprises a pitch adjusting portion and a loop including a tone-color forming portion and a delay portion. A signal circulating through the loop is delayed using an amount of delay by the delay portion; and then, the tone-color forming portion imparts a tone-color characteristic to the signal delayed so as to produce a sound signal. In the pitch adjusting portion, a pitch of the sound signal is detected; and an initial constant is generated based on a designated pitch and/or a designated tone color. The initial constant represents an initial delay effected by the delay portion. In addition, an amount of correction is created based on a difference between the pitch detected and the designated pitch. Thus, the amount of delay of the delay portion is corrected by using the amount of correction in such a way that the pitch of the sound signal is automatically adjusted to be equal to the designated pitch in real time. Moreover, the delay portion comprises an integer delay portion and a decimal delay portion, wherein the integer delay portion has a first delay time which corresponds to a number of delay stages each representing a unit time of delay, while the decimal delay portion has a second delay time which is smaller than the unit time of delay. By delicately controlling the amount of delay, it is possible to adjust the pitch of the sound with accuracy.