Doepfer Dark Energy II - Manual (Page 30)

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Dark EnerGy II DOEPFER Nuts and Bolts of Sound Generation
Low Frequency Oscillators
An LFO is a Low Frequency Oscillator which generates continuous control voltages over a wide range. It
can produce several waveforms. Both LFOs of Dark Energy II produce triangular and square waveforms.
The latter can be used for “trills” in modulation, while the former creates a continuous “up and down” modu-
lation. The LFOs can be used as modulation sources for all of Dark Energy II’s crucial parameters.
Interaction
The following figure shows the interaction of all the components mentioned above. It shows the audio signal
path (shaded) with oscillator (“crude sound”, “pitch”), filter (“timbre”) and amplifier (“loudness”). In addition
to these modules you will see the modulating or controlling elements (envelope generator, LFO) which pro-
duce the control voltages necessary to control the parameters of the aforementioned components.
Keyboard /
MIDI-Interface
Oscillator
(VCO)
Filter
(VCF)
Amplifier
(VCA)
Low Frequency
Oscillator
(LFO)
Envelope-
Generator
(ADSR)
Audio
Output
Gate Signal
Envelope Control Voltage
LFO Control Voltage
Pitch
Control Voltage
Audio Audio Audio
If you feel like going deeper into the secrets of sound synthesis, please check out this book:
Allen Strange, Electronic Music - Systems, Techniques and Controls, 2nd edition, Wm. C. Brown Company
Publishers, Iowa, ISBN 0-697-03602-2
This is one of the most comprehensive and useful publications about sound synthesis and synthesizers –
recommended reading essential for newcomers and advanced musicians alike.