Aachorripsis
Implementation of Iannis Xenakis composition Aachorripsis in SuperCollider based on his notes in Formalized Music.
Installation
Install this extension as a quark via
Quarks.install("https://github.com/capital-G/Aachorripsis.git");
// restart sclang
thisProcess.recompile;You can update it via
Quarks.update("Aachorripsis");
thisProcess.recompile;Usage
AachorripsisGUI allows you to generate and examine a matrix (according to Formalized Music) as well as starting a Tdef with the name \aachorripsis.
Take a look into the provided aachoripsis-play.scd which also includes an example how to use the matrix events as gates or envelopes in an eurorack environment.
Implementation
When comparing the score and matrix with the written notes in Formalized Music there are some discrepancies which are documented in this section.
Normal distributed density
A 2-event shall have a fixed density of events which originates from the poisson distribution.
This becomes obvious when comparing why a single event has the density between 3.5 and 6.5 while it averages around 5.0.
Therefore it seems that within all 2-events there is a deviation and after some plotting I think Xenakis applied a normal distribution among the density of each event class, therefore I added the sigma parameter which allows to control the variance of the normal distribution and therefore the spread of its values around the mean.
Wood block sample
Xenakis is infamous for his use of wood blocks in compositions - listen e.g. to Metastaseis. Although it is not noted in Formalized Music the wood block appears in parts with low or no density in the score of Aachorripsis. I assume that it was used in sparse sections to provide some orientation, therefore it is also played back here in sparse sections as it also is a trademark of Xenakis.
Also the orchestral score released by Bote & Bock does not give any hints of the origins of the woodblock hits.
The included sample is provided by lostphosphene via freesound.org.
Performance
The source code was written for a concert on 2022-10-25 in honor of Xenakis 100th birthday. Instead of the 7 instrument groups it was performed with 2 modular synthesizer systems which received 7 gates to trigger musical events. See the website of the concert for further details.
License
GPL-2.0