Album by Risto Holopainen, released in 2015
available at bandcamp.
Some of the pieces of Signals & Systems explore algorithmic composition using autonomous instruments. Typically, the autonomous instruments work on the low level of sound synthesis and run uninterrupted to generate an entire composition. However, the composition process did not stop at that point; the output from the algorithms was further treated in a long process of acoustic processing and mixing. The digitally generated sounds were played through loudspeakers prepared with aluminium foil which adds its distinct rattling distortion, and then recorded and further mixed. Although the acoustic processing has left its mark on the sounds, the pieces survive in the form they emerged from the algorithms.
In automatic writing as practiced by the surrealists the goal is to put your criticism aside and let the unconscious leap forth. In some sense the output of autonomous instruments can be like automatic writing; what they produce may be recalcitrant pieces of music that a critical curator might not endorse. Nevertheless, the algorithms behind the pieces were not written in one go, but were themselves the result of an iterative process of improvements.
This field recording from a building site introduces material that is used in some of the other pieces.
Algorithmic csound composition in which motifs are transformed by a dozen or so different functions.
This composition is the output of a single C++ program, implementing four autonomous instruments running in parallel and interacting with each other. This is perhaps my most radical exampel of a composition realised entirely with autonomous instruments.
Yet another algorithmic composition, this time focused on the evolution of a melodic line. A random sequence of transformations act on the theme and causes it to metamorphose.
A brief recorded sound segment is iteratively processed using something that may be described as an adaptive, nonlinear waveguide. The process also runs in the reverse direction.
A short collage work, featuring some custom nonstandard synthesis, time and pitch data from bird chirps taken from Scaffolding, a few other samples and some tin foil.
An encore for what it's worth: Scaffolding doubled.