Cadaver: Cadavre Exquis Scanner
The Cadaver is a scanner and 8 VCAs with voltage control over width and center. The scanner is based on Grant Richter's voltage controlled electro-optical mixer. The design is described as an implementation of the surrealist concept of exquisite corpse or rotating corpse. An example of serial blind composition. It is similar to the cut-up technique of composing a story. The VCAs are simple linear VCAs with voltage control.
The scanner is a vactrol based circuit, so organic and imprecise results should be expected. The scanner control circuit is esentially a bar graph IC set in point mode with dither from an LFO. The VCAs are before the scanning vactrol circuit. The vactrols give a rudimentry crossfading or interpolating effect for smooth transitions.
These videos all show examplse of other systems doing what the scanner is capable of:
areP - Zack Dagoba (ARP2500 Mix Sequencer)
RxMx & Cadavre Exquis - Make Noise (RxMx)
Cadavre Exquis Square - David H (Cadavre Exquis Spatial)
CC BY-NC-SA 4.0
Schematic
PCB Layout
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Panel Design
Bill of Materials
Tuning and Calibration
The only calibration required is for the WIDTH CV and CENTER CV input attenuverters. With a CV input and the potentiometer in the 12 o'clock position the output should be 0V. Adujst trim potentiometer to calibrate.
Patch Programming
8 VCAs
To use as 8 plain VCAs you simply turn the WIDTH potentiometer to its maximum and the CENTER potentiometer to the center. This will set all outputs of the scanner to fully open, thus allowing the VCAs to output whatever their level is set to.
Scanner
To make an oscillator first patch the EOC into the TRIG or set the CYCLE switch to repeat. The slope generator will start to oscillate with the frequency determined by the RISE and FALL pots.
Ping Pong: Set the WIDTH potentiometer to minimum and CENTER potentiometer to 12 o'clock. Use a triangle wave for CENTER CV. Adjust CV potentiometer until the indicator LEDs show the open gates bounce back and forth.
Looping: Set the WIDITH and Center potentiometer to minimum. Use either a ramp or saw wave for CENTER CV. Adujust the CV potentiometer until the indicator LEDs show a looping effect. Ramp input will loop 1 to 8 and saw from 8 to 1.
Variable Width: Use the WIDTH CV input. This can be used in concert with center point animation.
Cadavre Exquis
To achive cadavre exquis all that is required is a random stepped voltage into the CENTER CV. This randomly selects between the channels of the scanner creating the cut-up composition.