Sound create use FM synthesis use C program. Use 0.4*expf( -time ) envelop. Algorithm 5 of YM2515 chip (not use chip, only follow its algorithm in C program) • No feed back • ampl_m1 = 0.584 • ampl_m2 = 0.842 • ampl_c1 = 0.826 • ampl_c2 = 0.842 • freq_m1 = 239.935 Hz • freq_m2 = 69.058 Hz • freq_c1 = 17.138 Hz • freq_c2 = 69.058 Hz