Microsound (review)

As a confessed bibliophile, the first thing that struck me about Curtis Roads's Microsound was simply its appearance. The slightly squarish proportions and abstract cover design set it apart from most computer music texts. Luckily, the contents live up to the expectations generated by its striking physical exterior. This is a valuable resource for anyone interested in the realm of quantum acoustics.

Microsound may surprise some readers expecting a companion volume on granular synthesis to the author's earlier text, The Computer Music Tutorial. This new book is much more personal and subjective, concentrating heavily on Mr. Roads's own research and compositions using sound particles. The secret to understanding the tenor of Microsound lies in the Acknowledgments section. This publication derives from Mr. Roads's 1999 doctoral thesis, "Synthèse et Transformations des Microns."

Just after the Acknowledgments is a nice overview of the nine chapters that constitute Microsound. In the first couple of chapters, Mr. Roads takes the reader on a journey through the history of time structures in music, leading to the history of "microsound," which he defines as a broad class of sounds that extends from the threshold of timbre perception up to the duration of short sound objects spanning the boundary between the audio frequency range and the infrasonic frequency range. The middle chapters deal directly with sound particles, discussing the different types and their possible transformations. The later chapters are more personal, covering compositional applications, aesthetics of composing with micro-sound, and a commentary on the future. Occasionally Mr. Roads jumps around from mathematical and historical facts to personal opinion rather quickly, and as a result some of his beliefs are presented without an adequate qualifier, but he usually keeps these two worlds separated.

Chapter 1 reminds me of the visualizations that start off with a view of the universe and zoom in closer and closer—galaxy, solar system, earth, city, house, person—until a single strand of DNA fills the screen. Mr. Roads travels through time scales in a similar fashion, zooming from the infinite to infinitesimal in nine steps. He places Microsound at the sixth level between Sound Object and Sampled Sound. This chapter is useful because it helps contextualize where exactly microsounds lie in the time domain. It is very easy to say that sound particles last between 1 and 100 msec, but relating this length to other units of perception places the subject of this book in a nice framework.

Chapters 2 and 3 are a wonderful blend of history and mathematics sprinkled liberally with relevant quotes from expected sources such as Henry Cowell, Karlheinz Stockhausen, and Iannis Xenakis, but also from philosophers, poets, and physicists such as Titus Lucretius, Margaret Cavendish, and Stephen Hawking. These two chapters offer a comprehensive overview of the development and implementation of granular synthesis. Mr. Roads feels that these chapters prepare the reader to understand concepts presented later in the book, but I think they give the computer music community a resource it has been sorely lacking—namely, a single, well-documented source for the composer or researcher who wants to begin working with sound particles.

For people already familiar with the basic ideas and techniques of granular synthesis, chapters 4 and 5 are the heart of this book. Here Mr. Roads explains the different types of particles, including glissons, grainlets, pulsars, and trainlets. Table 4.4 on page 177 is a well-organized reference detailing the envelope type, waveform, and characteristics of each of the grain types discussed in the chapter. Chapter 5 nicely explains the synthesis and transformation of microsounds, without the use of windowed spectrum analysis. Chapter 6 covers more documented topics including short-time Fourier Transforms, phase vocoding, and an introduction to the Gabor transform. This revises and updates material already covered...