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  • About This Issue

The composer Edmund Campion, who was associated for several years with the Institut de Recherche et Coordination Acoustique/Musique (IRCAM) in Paris, now serves as co-director of the Center for New Music and Audio Technologies (CNMAT) at the University of California, Berkeley. Many of his electroacoustic works exhibit an interest in combining formal composition with guided improvisation. In an interview in this issue, Mr. Campion discusses, among other topics, how he uses real-time audio signal analysis to achieve interactivity between the computer and the performer. In works like Corail, for example, a Max/MSP patch "listens" to the performer's rhythm, pitch, articulation, and timbre, and responds by projecting related sounds into the surrounding space, influencing the performer's subsequent musical choices.

Computer music having originated in the West, its tools not surprisingly tend to be oriented, sometimes unconsciously, toward models of Western music, and moreover toward those aspects most easily captured by traditional music notation and nomenclature. However, a great deal is to be learned by applying technological research to nonwestern art forms. Bret Battey's article in this issue introduces a technique for analyzing the highly expressive pitch curves in Indian classical music, along with corresponding trajectories of amplitude and spectral centroid. His method involves segmentation into phrases, identification of critical inflection points, and fitting of Be´ zier splines to the data between those points. The author details the mathematics behind his approach and also presents sound examples demonstrating his software's output. He advocates wider incorporation of Bé zier splines in computer music applications, following the lead of computer graphics.

In the next article, Pete Symons gives a mathematical overview of a common component in digital sound synthesis: the second-order direct-form recursive oscillator. This algorithm offers computational simplicity and low distortion. However, the author shows how the oscillator encounters problems and can produce audible clicks when constant-amplitude, phase-continuous changes of frequency are expected. To mitigate these problems, he has arrived at a procedure that computes new initial conditions (defined as functions of amplitude, frequency, and phase) at each frequency transition.

A number of researchers have tackled the problem of automated classification of music. The article herein by Rudi Cilibrasi, Paul Vitányi, and Ronald de Wolf presents their technique, which takes MIDI files as input but has no built-in knowledge of music. The method is based on a general-purpose similarity metric called the normalized compression distance, which has been applied in fields as diverse as astronomy, genomics, and linguistics. The authors summarize experiments showing that their approach can distinguish between various musical genres and can even cluster pieces by composer.

Our final article, by Steven Jan, proposes a memetics of music and a methodology for initial forays into this territory. Richard Dawkins, who coined the term "meme," described it as a unit of cultural transmission, and mentioned melodies as one example. By analogy with genes, memes are said to propagate themselves from brain to brain, with the most successful transformations surviving. Mr. Jan's article suggests that music theorist Eugene Narmour's [End Page 1] implication-realization model, based on Gestalt principles, provides a good foundation for musical memetics. The author then relates how he put the Humdrum Toolkit (described in our Summer 2002 issue) into service to detect possible memes in the music of Haydn and Mozart.

The proliferation of audio and music tools on the Linux platform was outlined in an article by Dave Phillips in the Winter 2003 issue of Computer Music Journal. In the present issue's Reviews section, Mr. Phillips relates recent developments in evidence at the Second International Linux Audio Conference, held again at the Zentrum für Kunst und Medientechnologie (ZKM) in Karlsruhe, Germany. Also reviewed in this issue are two other events, a new edition of a textbook on electronic music, and numerous CDs.

As in 2003, the annual Computer Music Journal disc accompanying the Winter issue is a DVD rather than a CD. We thank Takayuki Rai for serving as curator for the audio and multimedia compositions by Japanese composers on this year's disc. The annual disc also always includes sound examples to accompany recent articles...

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