Doepfer A-100(~ 40 MB) - Manual (Page 267)

doepfer System A - 100 VCF 1 A-120
5
5. User examples
The filter’s cut-off frequency can be modulated in
various ways:
• VCF - LFO
Modulation of the cut-off frequency produces cycli-
cal changes of the sound spectrum. At low
frequencies (c. 1 - 5 Hz), you get a "Wah-Wah"-
effect. Modulation in the audio range produces
interesting sounds; the same principles apply here
as with frequency modulation of the A-110 VCO
(see chapter 6).
• VCF - ADSR
Modulation by an envelope results in gradual
change of the sound spectrum. Typical uses
would be the synthesis of electric bass or drum
sounds, and filter sweeps, which slowly sweep
through the audio spectrum, emphasising different
harmonics.
• VCF - Keyboard CV
This modulation produces pitch-related filter ope-
ning: the higher the pitch, the more the filter opens,
and the brighter the sound becomes.
Producing wind FX with A-120 and A-118
D Patch coloured noise into the audio input, and
random voltage CV into CV2. Set the filter CV to 0,
cut-off to a middle value, and the resonance just
below self-oscillation.
D Now turn CV 2 up. A whistling wind sound will
occur. You can control the rate and amount of its
irregularity with controls 3 and 4 on the A-118, and
the tone colour with the A-118’s controls 1 and 2.
Fig. 3: Creating wind effects
Blue
Colored
Random
Output
Rate
A-118
NOISE / RANDOM
Random Control
- +
Red
Level
Resonance
CV 2
Audio In
Level
Audio
Out
CV 2
Frequency
A-120
VCF 1