Alesis Fusion Tutorial page 20

ALESIS FUSION
With this 'rule', it becomes considerably easier to control sounds. For example, if we have a
keyboard that generates 1 volt for every octave, we can 'play' the pitch of the oscillators
6
musically .
And what do you think would happen if we had a device that generated a slowly rising and
falling voltage that was applied to pitch (i.e. oscillator frequency)? Such as this:
+1V
0V
-1V
That's right - the pitch will slowly rise an octave and then fall two octaves and then rise again,
etc., as the voltage rises and falls. What about this?
+1V
0V
-1V
That's right - the pitch will rise slowly and then drop abruptly and rise again as the voltage slowly
rises then drops suddenly. And this?
+1V
0V
-1V
Correct! The pitch will jump up and down abruptly. In fact, given the 1V/Octave rule, this would
be an octave jump/trill between the two extremes.
Congratulations! You now understand how the LFO (low frequency oscillator) works!!!
6 It sounds all so rudimentary now but back then, this was cutting edge! Previously, the only way
to pitch an oscillator was to record little snippets of an oscillator (the pitch of which was set
manually) and then splice the bits of tape together to create a 'melody'!!
Controllers
ANALOG SYNTHESIS TUTORIAL
Page 20