FM Synthesis
In FM synthesis, an envelope generator is inserted between the modulator and the carrier so
that there is control over of how much of the frequency modulation is taking place with respect
to time.
Adding this envelope constructs the basic FM building block as illustrated below:
0
50
90
50
0
Attack
Decay
MODULATOR
FM ENVELOPE
CARRIER
OUTPUT WAVEFORM
It can be seen that as the attack rises (and the modulation level gradually increases), the output
waveform becomes increasingly more complex (harmonics are added) and when the envelope
is at its peak, the output waveform is approaching a square wave in shape.. It then returns to a
simple sine wave again as the envelope (and hence the modulation level) decays to zero.
OSC 2 is able to frequency modulate OSC 3 via a dedicated FM envelope:
Osc 2
A/R envelope
Osc 3
It is important that it is realised that the FM envelope is used only for FM purposes and is not
one of the envelopes available on the V-Station’s MAIN panel.
Although the FM synthesis capabilities on the V-Station are not as extensive as those found
on other synthesizers that specialise in FM synthesis, it is nonetheless capable of producing
some excellent electric pianos and tuned percussion sounds not normally available on
subtractive analogue synthesizers. Plus, of course, you can run your FM sounds through the
V-Station’s filter for a range of sounds not normally possible on FM synths.
The easiest way to be totally familiar with FM is to try out some of the factory presets that employ
FM. For example, Program 209 is a bell sound that relies on FM and Programs 135 and 145 are
electric pianos - experiment by modifying the various FM settings.
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Synthesis Tutorial
