I give you simplified FM synthesizer. Try the following program with various B and M. ACLS B=1:M=2 ST$="" FOR I=0 TO 31 T=I/32 V=120*SIN(2*PI()*T+B*SIN(2*PI()*M*T)) V=ROUND(V+128) ST$=ST$+HEX$(V,2) NEXT I WAVSET 255,127,127,127,127,ST$,69-48 BGMPLAY"@255O4CDEFGAB"