About This Issue

Karlheinz Stockhausen’s life ended a year ago, but the influence of this giant of 20th-century composition will long persist. Licht-Bilder, the third scene of the opera Sonntag from his monumental Licht cycle, premiered in 2004. When Licht-Bilder was performed at the Zentrum für Kunst und Medientechnologie (ZKM) in Karlsruhe later in 2004, Ludger Brümmer of ZKM interviewed the composer. This issue of Computer Music Journal includes a new translation of that interview, which focuses on Stockhausen’s approach to electronics, using Licht-Bilder as a point of departure for amore general discussion. Stockhausen outlines his vision for futuremusical development in the parameters of dynamics, timbre, and space. He then answers questions on the role of the composer and on the use of machines, describing the inception of a composition as “hearing something as if in a dream.”

The cover of this issue announces “Parametric Piano Synthesis,” the subject of the article by Jukka Rauhala and his co-authors. The emulation of traditional musical instruments has long served as a touchstone for sound-synthesis techniques, because those sounds are so familiar that any limitations of a technique tend to leap into focus more quickly than when the technique is applied to creating novel sounds. “Sampling synthesis” solved that problem by simply using audio recordings of the instruments. The utility of sampling synthesis is illustrated by the ubiquitous digital piano, whose effectiveness owes much to the fact that piano notes are discrete and have few control parameters, allowing them to be reproduced using a limited set of recordings.

However, there are some advantages to synthesizing the sounds of musical instruments, even the piano, without using recordings. These include drastically lower memory requirements (an important consideration for hand-held devices) and the ability to achieve useful timbral variations by manipulating synthesis parameters in ways that might or might not mimic the physical instruments.

The article by Rauhala et al. presents a physics-based approach to synthesis of the piano. (Sound examples are included on the DVD that accompanies this issue.) Their technique employs a digital waveguide model of the piano string, as well as simulations of beating, sympathetic resonance, and the knock of the hammer strike. The synthesis algorithm permits real-time control of parameters such as inharmonicity and fundamental frequency. This real-time control not only speeds the task of tuning the model for a specific target sound but also encourages the creative exploration of timbres impossible to achieve with real pianos. The authors describe the model’s implementation in PWGL, a Lisp-based graphical patching environment for composition and synthesis.

A related environment for computer-aided composition is OpenMusic, which like PWGL has roots in the PatchWorks software developed in the late 1980s and the 1990s. The article by Jean Bresson and Carlos Agon introduces a new object in OpenMusic, called the sheet. A longstanding problem in music representation concerns how to align traditional notation with simultaneously depicted linear-time functions, such as audio waveforms and graphs

of MIDI data. Instead of warping the music notation to fit a strictly linear time axis, the sheet object embodies the opposite priority, warping the linear-time objects to align with the non-proportionally spaced symbols in the music notation. The authors also discuss other features of the sheet and general problems of score representation in computer music composition. The objects within the tracks in a sheet can be constructed algorithmically using OpenMusic patches embedded within the score. Objects can be inspected and manipulated using various editors in OpenMusic, and functional relations can be established between them.

The article by Dionysios Politis et al. presents a very different type of software for notating and synthesizing music. The focus here is not on visual programming or on computer-aided contemporary composition, but on assembling and auditioning music in the style of ancient Greece. After an overview of the materials of ancient Greek music and the sources from which scholars understand it, the article presents two pieces of software. One is a simple Flashbased interactive demonstration that introduces novices to the features and speculated sound of the kithara, an ancient stringed instrument. The other is a more...