Evolution

The Evolution module is inspired by the Turing Machine Eurorack module. The purpose is to generate "controlled randomness". But, instead of pure random input, here the input can be taken from two CV ports.

How does the algorithm work?

Evolution is based on a shift register, which can be thought of as a sequence of sample&hold units. The shift register as a length of 16 steps. At every trigger pulse, the values of all sample&hold units are passed to the next s&h in the chain. The new value of the first element is determined by the other CV inputs or knob values.

If "REPLACE" is all the way down (at 0) the value of element corresponding to the last value of a LENGTH long register will be copied back to the first element. This gives rise to a repeating pattern of LENGTH steps. With increasing value REPLACE it is becoming more likely that the first value will be taken from inputs A or B, which is determined by the value of PARENT.

The MIX parameter determines another aspect of the CV replacement. MIX=0 retains the old value (independent of REPLACE or PARENT), a MIX between 0 and 1 mixes a fraction of the new (A or B) into the old value.

The OUT1 port gives the value of the head of the shift register, i.e. just the value which has been operated on, while OUT2 gives a value from further into the shift register chain. The offset can be set by the small knob.

NOTES:

Make sure you your trigger does not get delayed more than the CV input. For example, if you use a SEQ-3 sequencer to provide CV input to A and B and also the SEQ-3 GATE output to the Trigger input of Evolution, all is fine. If, however, you introduce a quantizer or scaler inbetween the SEQ-3 and the Evolution, you should delay the trigger signal by the same amount, otherwise the signal will change AFTER the trigger arrives, and the trigger stores the old value.

This is not a problem of Evolution, but simply a fact of digital (sample-wise) processing. The same is true for the normal S&H or any 'sampling' module.