Abstract: A musical sound synthesizing apparatus which simulates a sound generating mechanism of a string instrument by using an electronic circuit comprises a driver for applying data, an adder, a delay unit for storing data temporarily, a low pass filter for processing data, and a word length designating unit for designating a word length (address width) of the delay unit. The adder, delay unit and low pass filter form a loop-shaped circuit, with their corresponding input ends and output ends connected with each other. The word length designating unit corrects a word length of the delay unit in accordance with a phase delay of the low pass filter or in accordance with the number of stages of the pipeline structure of the loop. In the case where a musical sound of the type generated by touching or hitting strings is synthesized, the driver reads at least two series of data stored beforehand and applies the read data to one of the inputs to the adder.