# Légende (Studie) (2019)

stereo piece, duration 4’34”. An algorithmic tape piece commissioned for the Dumpf Edition CD #12 “SEGMOD”, curated by Martin Lorenz.

Légende is a study in the ability of the seg-mod algorithm to function as a “basis space” to which any digital signal can be decomposed. It is seemingly more complex (too complex?) than typical bases used in signal processing such as the linearly spaced series of fixed frequency oscillators of the Fourier transform, while having some interesting constraints such as the lack of amplitude weighting. The material input to the piece is the narration of the dystopian Alpha 60 computer, produced through a mechanical voice box and thus already hybrid between machine and human. In the first section, decomposition is accomplished by iteratively matching all possible combinations of 1024 frequencies that have even periods at the CD sampling rate of 44.1 kHz, always selecting the path closest to the sound input using the Dijkstra algorithm, then proceding with the “error signal” and a slightly reduced amplitude, until the residual signal is sufficiently faint. The second section exploits the signal’s new “representation” thus obtained to apply stretching and interpolation, deviating from the integer periods and introducing the pumping of shifting phase transitions, for instance revealing a prior Nyquist frequency used as a loophole to inject silences.