About This Issue

The year 2007 marks several major tificial intelligence. Examples of Mr. composition so that its timbre and its anniversaries in computer music. Cope’s compositions appear as music tuning system would be linked, anal- First of all, a half-century ago twin notation in this interview and as au- ogously to the linkage between the disciplines were born: 1957 wit- dio on the DVD accompanying the harmonic series and the simple- nessed the premiere of the first musi- next issue. integer frequency ratios at the heart cal composition created by computer Proceeding chronologically, the of the traditional Western scale. He algorithms and also the first algorith- year 2007 also represents the 40th realized that if he used powers of the mically synthesized audio samples. anniversary of the invention of the Golden Mean (approximately 1.618:1) At the University of Illinois, Lejaren sound-synthesis technique that even- for his FM algorithm’s carrier-to- Hiller and Leonard Isaacson com- tually brought digital synthesis out of modulator ratios, the resulting in- pleted the Illiac Suite, a composition the laboratory and to the masses. In harmonic spectra would contain for string quartet whose notes were 1967, John Chowning of Stanford frequency components related by the determined by a computer program. University, while experimenting same interval. Therefore, pairing And at Bell Laboratories, Max Math- with a version of Music IV, noticed these spectra with a tuning system ews introduced Music I, the first of the rich and dynamically controllable based on a Golden Mean “pseudo- what came to be known as the Music spectra produced by linear frequency octave” could yield an alignment of N family of languages: software for modulation (FM) at audio rates (which partials similar to that which occurs generating sequences of numbers differs from FM radio in that the car- when notes having harmonic spectra rendered through a digital-to-analog rier frequency lies in the range of are tuned to the traditional musical converter as audio waveforms and hearing and the signal never gets de- consonances. The Golden Mean per- controlled at a higher level as musi- modulated). FM sound synthesis was vades this composition, from the cal notes. subsequently employed in Jean- lowest level of sound synthesis, In honor of the birth of computer- Claude Risset’s Mutations (1969) and through the choice of pitches, to the based algorithmic composition, we many later computer-synthesized highest level of musical form. Beyond present an interview with one of its compositions, and in time it sur- its algorithmic use of the Golden best-known practitioners, the one faced as the engine behind Yamaha’s Mean and FM synthesis, Stria could who also has probably engendered groundbreaking digital synthesizers, also be considered computer-inspired the most controversy outside the notably the DX7. in its use of the recursive program- field, because of his computer emula- Thirty years ago, John Chowning ming paradigm, which had first been tion of historical styles. David Cope’s created the piece that many regard as introduced in the LISP programming work is well known to readers of this his finest. Stria received its premiere language and which was available in journal, thanks to his articles pub- in October 1977 in Paris. In a number the Stanford Artificial Intelligence lished herein and elsewhere, but es- of ways, Stria represents a quintes- Language (SAIL) that John Chowning pecially owing to his series of books sential computer music composition, employed (along with Music 10) for and CDs on algorithmic composition. being so intrinsically dependent upon Stria. The creative and philosophical This interview with Mr. Cope takes a computer for its realization. Before implications of recursion must have a decidedly nontechnical tack, composing Stria, Mr. Chowning had been “in the air” during that period; largely avoiding engineering details spent much time experimenting with the visual beauty of fractals—un- and instead revealing the composer’s the sorts of spectra that could be cre- known to Mr. Chowning at the perspectives on aesthetics, style emu- ated by FM synthesis. For Stria, he time—had been discovered a few lation, creativity, authorship, and ar- sought a novel way to structure a years before, and soon afterward,

Front cover. John Chowning cre- The artwork also incorporates in- Back cover. An excerpt from the ated this time-versus-pitch diagram version calligraphy drawn in 1978 opening pages of David Cope’s of his composition Stria from score by Scott Kim (© 2007 Scott Kim, Emmy-Beethoven Symphony, move- data derived by Olivier Baudouin, scottkim.com; used by permission). ment #1. (Reprinted with permission Kevin Dahan, and Matteo Meneghini. of David Cope and the publisher, Spectrum Press.)

About This Issue 1

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/comj.2007.31.3.1 by guest on 24 September 2021 Douglas Hofstadter (who had some Stockhausen and Iannis Xenakis. sions of the piece and traced their conversations with the composer at Similarly, the research described origins. The final two authors, Stanford around then) published his in the present issue has led to the composers Olivier Baudouin and bestselling book Gödel, Escher, Bach, reconstruction of Stria in modern Kevin Dahan, have managed to re- which expounded upon recursion and computer languages. John Chown- implement Stria in current program- self-similarity along with related top- ing’s own brief article in this issue ming languages—no small feat, ics such as self-referentiality, artifi- serves as an introduction to the other considering that SAIL and Music 10 cial intelligence, and consciousness. four articles, explaining how the au- are obsolete languages and that part Although Stria’s source code employs thors, from several disciplines, came of Stria’s source code is lost. The an- recursive programming sparingly, the to be involved in projects related to nual DVD accompanying the next integration and unification of mul- Stria. Computer scientist and electri- issue of the Journal will contain not tiple levels clearly represent a major cal engineer Matteo Meneghini’s ar- only audio for the reconstructed compositional goal in this work, and ticle (written, like the others, in close Stria, but also video showing a spec- the Golden Mean itself expresses a consultation with John Chowning) trographic visualization of the piece, self-similar relationship. presents a detailed explanation of as well as scanned documents from The rest of this issue’s articles Stria’s compositional technique, the Stanford University library form, in effect, a special issue devoted based on the author’s examination of archives, such as the remaining origi- to a new understanding of Stria. The the composer’s original source code. nal source code and the composer’s Summer 2000 issue of Computer The article by Laura Zattra, on the notes. We thank the authors and es- Music Journal showcased “new im- other hand, presents an equally fasci- pecially John Chowning, without plementations of electroacoustic nating study having a musicological whose help this special issue would classics,” specifically, recent realiza- perspective based on philology. not have come to fruition. tions of older works by Karlheinz Ms. Zattra uncovered multiple ver-

2 Computer Music Journal

Downloaded from http://www.mitpressjournals.org/doi/pdf/10.1162/comj.2007.31.3.1 by guest on 24 September 2021