APPENDIX SIX



40   IF STICK(0) = 14 THEN A = A + 1:
    IF A > 255 THEN A = 0: GOTO 20
50   IF STICK(0) = 13 THEN A = A - 1:
    IF A < 0 THEN A = 255: GOTO 20
60   IF STICK(0) = 7 THEN B = B + 2:
   IF B > 14 THEN B = 0: GOTO 20
70   IF STICK(0) = 11 THEN B = B - 2:
    IF B < 0 THEN B = 14: GOTO 20
80   IF STRIG(0) = 0 THEN C = C + 1:
   IF C > 15 THEN C = 0: GOTO 20
90   GOTO 20

You move the stick up or down to change pitch, right or left to change
the distortion level. Press the trigger to change the volume level. See
Softside, #30 for a similar program using all four voices and Santa
Cruz's Tricky Tutorial #6 (sound). You should also examine Atari's
Music Composer cartridge; it is not only a fine program, but it also has
excellent documentation on music, sound, and composition. There are
two excellent programs from APX, Sound Editor and Insomnia, both of
which allow you to create sounds to include in your programs (not
tunes however). Insomnia is particularly interesting in that it creates
sound which is played during the VBLANK intervals.