Logistic Equation an Analog Computer Module

Look at the schematic:








Pic of a komplet run of the LogGl from Klangbaukeoln.

With the schematic it is possible to understand this first order chaotic equation. Front picture shows the graph of it, so called „Feigenbaum diagramm“. After a few bifurkations chaotic parts begin. It has self similar sequences and it is for musical interest. It plays kind of melodies quite different from random stuff. Somtimes it is stabel and later it changes. Picture shows a few runs of it. Look closer to see bifurkations and chaos.

See video:

https:RND – Logistische Gleichung in Aktion


Further Links:

LogGl in action


how to build it


Doepfer at „Patch Examples“ you will find a complex patch to bring LogGl in action, a lot of work, but worth. Attention: Use a real s/h for best results!!

Thanks to Dan Slater in ComputerMusicJournal, 1998: 22/2: „Chaos Sound Synthesis“.


Modul is simple to use: A ext. Trigger causes an CV out in order of „Verteilungs“-pot is set. Result is simlar to oszi plot. Because of it chaotic structur it „plays“ endless similarties. Therfore I call it a melody generator and it is an intelligent boy not a stupid random generator. Have fun with it and feed a TwinPeak Filter.



+/- 26/5ma and  6hp/TE