Stria by John Chowning, the ultimate analysis!

Stria (1977) by John Chowning is a milestone in the history of computer music. My analysis of this wonderful piece is now published on the IRCAM site. It brings together the results of my now thirteen-year-old project.

I am particularly proud of this analysis. Together with John Chowning, I decided to create some explanatory videos where Mr. Chowning explains his FM and structural principles of the piece, based on the slides he usually displays during talks and conferences. Oral history, textual criticism and interpretation based on digital and audio sources, sketches, and other communications, are strictly intertwined. This is what distinguishes this online analysis I hope will be useful to scholars, students, composers, musicologists and to anyone interested in Chowning’s music and electronic music in general. A complete list of references related to the piece and to its principles completes the analysis.


Stria is a piece fully generated by the computer. It is famous for its use of the FM algorithm and the use of the Golden Mean Ratio (1.618).

I began my research on this piece back in 2003, when I met prof. Giovanni De Poli and Matteo Meneghini from the University of Padova. At the time, Matteo was reconstituting the basic algorithms and structure of the piece and we decide to join our efforts. I was a musicologist, he was a computer sound engineer. Then our project grew involving Kevin Dahan and Olivier Baudouin (both were composers, musicologists and computer scientists). We published the 2007 issue of the Computer Music Journal: The Reconstruction of Stria, Volume 31, Issue 3 – Fall 2007.

In my article in the Computer Music Journal, I traced the various stages of the assembling process, from the very first synthesis in 1977 to two different and coexisting 4-channels and stereophonic versions (in 2007). My research was typically the work of a philologist/historian, based on computer sources from Chowning’s archive, audio and paper sources, Chowning’s sketches, oral communications.

The complete list of sources (most of them unpublished), sound files and programs for the two reconstructions of Stria by Olivier Baudouin and Kevin Dahan were published in the DVD in the Computer Music Journal 31:4, December 2007. The DVD included the reconstructed sound files and program of Kevin Dahan, the original quad sound files from 1977, and a 5.1 rendering of the Dahan reconstruction with a Princeton sndpeek visualization.

Then, the idea to help musicologists and philologists compare different versions of the same piece (which was the case of Stria, with its 2 coexisting historical versions), drew me and Nicola Orio (Univ. of Padova) to build ACAME. This was an automatic tool for the analysis of electroacoustic music that we tested on Stria.

  • Nicola Orio, Laura Zattra, “ACAME – Analyse Comparative Automatique de la Musique Électroacoustique”, Musimédiane n° 4 (revue audiovisuelle et multimédia d’analyse musicale), 2009.
  • Orio Nicola, Zattra Laura “Audiomatching for the philological analysis of electroacoustic music”, Proceedings of the 2007 International Computer Music Conference (Copenhagen), ISBN 0-9713192-5-1, pp. 157-164.

In the meantime, Kevin Dahan and Olivier Baudouin proceeded to re-synthesize this magnificent piece with new software, even discovering small and hidden details in the historical codes.

So now we have 4 versions of the piece, all of them “authorized” by John Chowning.

I discussed this interesting history in the following article as well:

  • Laura Zattra (2015), “Génétiques de la computer music”, dans Genèses Musicales, Nicolas, Donin, Almuth Grésillon, Jean-Louis Lebrave (eds.), Presses universitaires de Paris Sorbonne, pp. 213-238.

My analysis on the ircam site reconstitutes Stria history, its compositional process, FM principles, Golden Mean vertical and horizontal space and structure, and the story of its versions.

This is a very interesting case study for any scholars who is interested in authorial philology and critique génétique, I’m sure of that!


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