doepfer
Lev.
CCV
SCV
A-116
VCW
Audio In
Clipping
CV
Symm. CV
Clipping
Level
System A - 100
1. Introduction
Module A-116 (Voltage Controlled Waveform Processor)
veform modification of audio signals. It can produce
new waveforms from the standard VCO shapes, and
modulate these changes
The signal first of all goes through an
which can attenuate the signal as well as amplify it by
up to a factor of 2.
After the input amplifier, the signal goes through
parallel processors: a clipping circuit, and an
asymmetrical amplifier. The processed signals are
added together
VC Waveform Processor A-116
provides
and sent to the output.
voltage-controlled dynamic wa-
in real time.
input amplifier,
two
Audio Out
Clipping-Level
manually controllable, but can also be modulated by
control voltages, to produce complex, constantly changing waveforms.
and
Symmetry
amounts are not just
1
A-116
VC Waveform Processor
System A - 100
doepfer
2. VC Waveform Processor - Ov erview
A-116
VC Waveform Processor
Audio In
➊
Clipping
Level
Clipping CV
➋
Symm. CV
➌
Audio Out
➍
VCW
Lev.
10
0
10
0
CCV
10
0
SCV
10
0
Sym.
10
0
➀
➁
➂
➃
➄
Controls:
: Input ! amplifier level control
Lev.
1
Clipping Level : Clipping threshold control
2
3 CCV : Clipping CV attenuator
4 SCV : Symmetry CV attenuator
5 Sym. : Symmetry control
In / Outputs:
Audio In : Signal input
!
" Clipping CV : Clipping CV input
Symm. CV
§
Audio Out : Signal output
$
: Symmetry CV input
2
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System A - 100
VC Waveform Processor A-116
3. Controls
1 Lev.
The
input amplifier
1. Since the gain amount is variable from 0 up to a
factor of 2, you can attenuate as well as amplify input
signals.
2 Clipping Level
With control 2, you set the
in a range from -10 V to +10 V. Any part of a
waveform which was
that is, held at the threshold level (see Fig.1).
3 CCV
If you want to use a CV at input " to control or
modulate the clipping threshold, set the clipping con-
trol voltage level
SCV
4
Symmetry can likewise be controlled or modulated by
voltage control. Use attenuator 4 to control the
level of the symmetry control voltage at input §.
5 Sym.
’s gain can be set with attenuator
clipping threshold
this threshold is clipped -
above
with Attenuator 3.
level
metry VCA is a special amplifier which operates in the
amplification range from -1 to +1, so can amplify
negative as well as positive voltages (see Fig. 2).
Clipping
Level
0
0
Clipping
Level
Fig. 1: how the clipping level works
Symmetry, that is the g
symmetry VCAs, is altered by control 5. The Sym-
ain factor of the internal
3
A-116
VC Waveform Processor
System A - 100
doepfer
1.0 (Input Signal)
0.75
0.5
0.25
Fig. 2:In this example, a triangle wave is symmetrically
amplified by the internal symmetry VCA, with various
gain factors from 1.0 to -1.0
0
- 0.25
- 0.5
- 0.75
- 1.0
4. In / Outputs
! Audio In
Socket ! is the A-116 audio input.
" Clipping CV
The input to use for
threshold.
voltage control
§ Symm. CV
The input to use for
voltage control
$ Audio Out
Socket $ is the A-116 output.
of the
of
symmetry
clipping
.
5. User examples
The VC Waveform Processor A-116 is a very complex
module, which, especially through the modulation of
clipping level and symmetry parameters, can give any
number of sometimes drastic waveform transformations. It’s definitely worth systematically investigating all
its possibilities. There follow a few suggestions, which
may be helpful starting points.
D Begin with waveforms like sine and triangle waves,
which have few overtones. Experiment with different combinations of symmetry and clipping level,
and listen to the results.
D Fig. 4 shows an example of the different wa-
veforms which emerge from clipping a triangle
wave and putting it through different amounts of
symmetrical amplification.
Try modulating one parameter with an LFO while
D
keeping the other constant. Experiment with different LFO waveforms and frequencies.
Repeat this process with different settings for the
D
second parameter.
Try the same with the first parameter fixed, and the
D
second modulated by an LFO.
Modulate both the clipping level and symmetry at
D
the same time. Try different combinations of modulation, such as
4
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System A - 100
VC Waveform Processor A-116
• LFO (sine wave) for Symmetry,
LFO (square wave) for Clipping Level
• RANDOM for Clipping Level,
Modulation wheel for Symmetry
etc.
Try the same experiments with more complex (rich
D
in harmonics) waveforms like a square wave, sawtooth, PWM, FM, or ring modulated sounds, or
external audio, for the input signal. Listen to the
results and take note.
patch the original signal and the A-116’s output
D
into a mixer.
Try using the waveforms generated by the A-116 to
D
modulate other modules such as a VCF or VCA.
Try using as an input the signal coming from a ring
D
modulator or a synced VCO. You can also get
interesting results by feeding the output of the
A-116 into a ring modulator, or into the sync input
socket of a VCO (see Fig. 3).
By experimenting in these and other ways, you’ll soon
realise what a powerful and endless source of dynamic wave form variations the A-116 is.
VCO
A-114
Sync
VCO A-116
CV
Gate
Symm.
Mod.
Clipp.
Mod.
ADSR
LFO
Fig. 3: The A-116 used in combination with a ring mo-
dulator and synced VCOs.
5
A-116
VC Waveform Processor
System A - 100
v = 1
v = 0.5
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Input Sig nal
Signal after Clipping
Fig. 4: Example of how the A-116 processes a
triangle wave with a constant clipping
level and variable symmetrical amplifier levels.
6
v = 0
v = -0.5
v = -1
Signals behind Symmetry-
Signals after beeing processed
VCA with several gain
by the symmetry VCA with
settings 'v'
different settings of ‘v’
Sum Up
Output Signals
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