Doepfer A-137-1 Wave Multiplier I
Wave MultiplierA-137 is a voltage-controlled wave form multiplier (wave multiplier). The fundamental idea of ââa wave multiplier is the multiplication of the waveform of an incoming audio signal (eg triangle / sine / sawtooth of a VCO) within a period. This produces additional harmonics (harmonics) in the audio signal. The duration of the period and therefore the pitch of the signal remain unchanged, as opposed to a frequency multiplication such as the PLL module A-196.
The A-137 operates as a kind of "inverse low-pass filter", so it adds a harmonic signal. Additional harmonics are added, where a low-pass filter (eg A-120) filters out overtones from an overtone-rich signal. Therefore the best results are obtained with the A-137 in combination with comparatively low tone waveforms (eg triangle, sine) as input signal. The A-137 can also be used for high-frequency input signals (eg sawtooth), but the effect is not as spectacular as with a triangle signal.
The A-137 is a very highly developed waveform multiplier that allows much more features, interferences, and waveform manipulations than other similar models. In addition, all parameters are manually adjustable and additionally voltage-controlled. Here you can see the most important features of the module: The multiples parameter (manually and adjustable by control voltage) defines the number of waveform multiplications within a period. The two parameters Folding Level and Symmetry (both manually and adjustable by control voltage) set the upper and lower levels at which the convolution of the signal (ie the "flipping" of the wave) takes place. The diagram below shows the function of these two parameters. The Harmonics parameter (manually and adjustable by control voltage) adds additional harmonics ( in addition to the harmonics resulting from the waveform multiplication) by sharpening the waveform edges (gain and limiter) and adding overshoot peaks (attenuated waves to the edges).
- Input Level (to adjust different input levels for the optimal effect of the module)
- Multiples (number of curve multiplication, manual setting)
- Harmonics (adding additional harmonics with an effect similar to that of the resonance in filters, manual setting))
- Folding Level (value of the upper and lower convolution level, for explanation see the sketch below, manual setting)
- Symmetry (symmetry of upper and lower convolution level, for explanation see the sketch below, manual setting)
- Audio In (also suitable for control voltages!)
- Multiples CV In (control voltage input for the number of curve multiplications, with attenuator)
- Harmonics CV In (control input for Harmonics parameter, with attenuator)
- Folding Level CV In (control voltage input for the convolution level, with attenuator))
- Symmetry CV In (control voltage input for the convolution symmetry, with attenuator))
- Audio Out (output for the processed audio or control signal)
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