Commodore 128D - Page 142

Notice that so far, we have not specified all of the parameters in the
SOUND statement. Take line 60, for example:
60 SOUND 1,1,1, 0, 0, 0, 3, 0
The three zeros following 1,1,1 pertain to the sweep parameters
within the SOUND statement. Since none of the parameters is speci
fied, the SOUND does not sweep. Add this line to your program:
100 SOUND 1, 49152,240,1, 0,100,1,0
Voice
Frequency.
Duration _
Sweep Direction
Minimum Sweep Frequency.
Step Value for Sweep
Waveform
Pulse Width for Variable Width
Waveform
LJ
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Line 100 starts the sweep frequency at 49152 and decrements the
sweep by 100 in the downward direction, until it reaches the mini
mum sweep frequency at 0. Voice 1, using the sawtooth waveform
(#1), plays each SOUND for four seconds (240 * 1/60 sec). Line 100
sounds like a'bomb dropping, as in many "shoot 'em up" arcade
games.
Now try changing some of the parameters in line 100. For instance,
change the direction of the sweep to 2 (oscillate); change the mini
mum frequency of the sweep to 32768; and increase the step value
to 3000. Your new SOUND command looks like this:
110 SOUND 1, 49152, 240, 2, 32768, 3000,1
Line 110 makes a siren sound as though the police were right on
your tail. For a more pleasant sound, try this:
110 SOUND 1, 65535, 250, 0, 32768, 3000, 2, 2600
This should remind you of a popular space-age TV show, when the
space crew unleashed their futuristic weapons on the unsuspecting
aliens.
Until now, you have been programming in only one voice. You can
produce interesting sound effects with the SOUND statement using
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USING C128 MODE—Sound and Music in C128 Mode
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