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The Stanford Center for Computer Research in Music and Acoustics (CCRMA) is a multi-disciplinary facility where composers and researchers work together using computer-based technology both as an artistic medium and as a research tool. CCRMA is located on the Stanford University campus.

Areas of ongoing interest at CCRMA include: Composition, Synthesis Techniques and Algorithms, Physical Modeling, Signal Processing, Digital Recording and Editing, Psychoacoustics and Musical Acoustics, Real-Time Applications and Controllers, Collaborative Works with other Art Disciplines and Music Manuscripting by Computer.

The CCRMA community consists of administrative and technical staff, faculty, research associates, graduate research assistants, graduate and undergraduate students, visiting composers, musicians and scholars, and industrial associates.

Center activities include academic courses, seminars, small interest group meetings, summer workshops and colloquia. Concerts of computer music are presented several times each year with an annual outdoor computer music festival in July. In-house technical reports and recordings are available, and public demonstrations of ongoing work at CCRMA are held periodically. _________________________________________________________________ CENTER FOR COMPUTER RESEARCH IN MUSIC AND ACOUSTICS Department of Music, Stanford University Stanford, California 94305

* Overview a detailed description of the current compositional and research activities

*Contents + Introduction to CCRMA + CCRMA Roster (September 1994) o Administration o Faculty and Research Staff o Graduate Student Research/Teaching Assistants o Graduate Students o Undergraduate Work Study Students o Undergraduate Music, Science, and Technology (MST) Majors o Visiting Scholars, Composers, and Consultants - 1994 and 1995 + CCRMA Facilities + CCRMA Courses * Compositional Activities * Research Activities + Computer Music Software + Rapid Prototyping for DSP, Sound Synthesis, and Effects o Reference + The Design of SynthBuilder-A Graphical SynthPatch Development Environment for NEXTSTEP + The CCRMA Music Kit and DSP Tools Distribution o Music Kit References o Highlights of the Music Kit 4.0 Release o Highlights of the Music Kit 4.1 Release + Common Lisp Music and Common Music Notation o References + Common Music / Stella: A Music Composition Language o References + A Dynamic Spatial Sound Movement Toolkit + DMIX + Physical Modeling and Digital Signal Processing + Digital Waveguide Modeling of Acoustic Systems o References + The 2-D Digital Waveguide Mesh + The Wave Digital Hammer + The Waveguide Piano Project + A Passive Nonlinear Filter for Physical Models + Synthesis and Research on Reed Driven Woodwind Instruments with Particular Emphasis on the Saxophone + Physical Modeling of Brasses o References + Feedback Delay Networks o References + Waveguide Reverberators and Real-Time Implementations o References + Synthesis of the Singing Voice using Physically Parameterized Model of the Human Vocal Tract + Adding Pulsed Noise to Wind Instrument Physical Models + Physical Modeling of Music Instruments using Neural Nets + FFT-Based DSP and Spectral Modeling Synthesis o References + Instantaneous and Frequency-Warped Signal Processing Techniques for Pitch Tracking and Source Separation and Fast Linear-Phase FIR Filter Theory and Design + Time-Frequency Analysis of Audio + Controllers for Computers and Musical Instruments + Real-time Controllers for Physical Models + Synthesis and Research on Reed Driven Woodwind Instruments + Ongoing Work in Brass Instrument Synthesizer Controllers + Performer-Oriented Brass Instrument Synthesis and Control o References + Haptic User Interfaces for the Blind + The Touchback Keyboard + Progress Report on the Radio Baton and Conductor Program + PadMaster: A Radio Drum Improvisation Environment + The Computer-Extended Ensemble + Real-Time Control Using Biological Signals o Related publications + Biocontrol Interfaces as Musical Instruments o References + Psychoacoustics and Cognitive Psychology + Applying Pychoacoustic Phenomena to the Coordination of Large Speaker Arrays + Distance of Sound in Reverberant Fields o References + Pitch and Repetition Rate Perception + Embedded Pitch Spaces an The Question of Chroma: An Experimental Approach o References + Musical Perception and Memory + Statistical Models for Psychoacoustic Research + Psychological Representation of English Vowel Sounds + The Perceptual Organization of Sound + New and Revised Psychoacoustics Textbooks * Archives + The International Digital Electroacoustical Music Archive: An Overview o Background and History o Founding Institutions o Boards o IDEAMA Branches o The Target Collection o Future Plans o Acknowledgements + The Catgut Acoustical Society Research Library o Background and History o Purpose and Goals o Activities


CCRMA is located on the Stanford University campus in a building that was refurbished in 1986 to meet its unique needs. The facility includes a large quadraphonic experimental space with adjoining control room/studio, an all-digital recording studio with adjoining control room, a MIDI-based small systems studio, several work areas with workstations, synthesizers and speakers, a seminar room, an in-house reference library, classrooms and offices. The building has been wired so that any office or workspace can connect with the workstation network. A gateway connects the workstations to the campus at large and also to national and international networks. A description of the hardware and software environment follows below.

The CCRMA hardware environment consists of an Ethernet network of workstations running the NEXTSTEP operating system (both NeXTs and Intel based PCs) and Macintosh computers. Digital signal processing is possible on the NeXT computers, both via built-in Motorola 56001 DSP hardware and on three Ariel Quint Processor boards which contribute five additional 56001 processors each. The Macintosh systems also provide DSP via Digidesign Sound Accelerator boards.

MIDI input and output are supported from Macintosh and NeXT computers. Digital audio processors include a Studer-Editech Dyaxis II system which can convert all popular digital audio formats as well as store and edit audio digitally, a Sony PCM-1610 3/4" video PCM system for mastering Compact Disks, several Singular Solutions analog and digital audio input systems for the NeXTs, and several Panasonic and Sony DAT recorders. Text and graphics are handled by an HSD color scanner on the NeXT system and by two NeXT Laser printers and an Apple Laserwriter 630 Pro.

The MIDI-based systems include various Macintosh computers with Yamaha, Roland and Korg equipment including Yamaha DX, TX, SY, TG and VL synthesizers, KX88 keyboard controller, Korg WaveStations, an E-mu Systems Emulator III sampler, and digital delays and reverberation. Other equipment available includes IVL pitch trackers, a Buchla Lightning MIDI controller, a Mathews Radio Drum controller, a JL Cooper MIDI patcher, Akai 32 channel MIDI-controlled audio patchbay and drum machines from Yamaha and Roland.

Studio recording equipment includes a 24 track mixer, an 8 track TEAC analog recorder, a Yamaha DMR8 digital recorder and mixing console, a TEAC 8 track digital recorder, various signal processing devices, Westlake monitor speakers and an assortment of high quality microphones.

The CCRMA software has been developed over a twenty-year period, and consists of a vast set of programs and system tools for editing, viewing, synthesizing, and analyzing sound. Much of the software was originally written in SAIL, a sophisticated Algol-like language for use on the previous mainframe and has been ported to the new workstation environment and developed further.

The programs currently in use are Common Lisp Music (CLM), an instrument compiling environment; and Common Music (CM), STELLA, and DMIX for compositional programming. Recent projects in music recognition, audio, signal processing, acoustics, psychoacoustics and physical modeling have been developed in languages native to the workstations, primarily Common Lisp, Objective-C, and Smalltalk. A graphical environment for real-time DSP research, SynthBuilder, is currently under development.


CCRMA is a part of the Music Department at Stanford University. Classes and seminars taught at the center are open to registered Stanford students and visiting scholars. The facility is also available to registered Stanford students and visiting scholars for research projects which coincide with ongoing work at the center.

Prospective graduate students especially interested in the work at CCRMA should apply to the degree program at Stanford most closely aligned with their specific field of study, i.e., Music, Computer Science, Electrical Engineering, Psychology, etc. Graduate degree programs offered in music are the DMA in Composition, and the Ph.D. in Computer-Based Music Theory and Acoustics. Acceptance in music theory or composition is largely based upon musical criteria, not knowledge of computing. Admission requirements for degree programs can be obtained directly from each particular department. CCRMA does not itself offer a degree.

The Music department offers an undergraduate major in Music, Science, and Technology. The specialization in Music, Science and Technology is designed for those students with a strong interest in the musical ramifications of rapidly evolving computer technology and digital audio and in the acoustic and psychoacoustic foundations of music. The program entails a substantial research project under faculty guidance and makes use of the highly multi-disciplinary environment at CCRMA. This program can serve as a complementary major to students in the sciences and engineering. Requirements for the undergraduate major are available from the Stanford Music Department.

Courses offered at CCRMA include:

* Music 120. Introduction to Composition and Programming using MIDI-Based Systems. Composition projects demonstrate participant's own software for voicing and controlling MIDI synthesis.

* Music 151. Psychophysics and Cognitive Psychology for Musicians. Basic concepts and experiments relevant to use of sound, especially synthesized, in music. Introduction to elementary concepts; no previous background assumed. Listening to sound examples important. Emphasis on salience and importance of various auditory phenomena in music.

* Music 154. Introduction to Computer Music: Survey of recent works and computer-based techniques.

* Music 192. Theory and Practice of Recording + 192A. Foundations of Sound Recording Technology. Topics: elementary electronics, physics of transduction and magnetic recording of sound, acoustic measurement techniques, operation and maintenance of recording equipment, recording engineering principles.

+ 192B. Advanced Sound Recording Technology. Topics: digital audio including current media, formats, editing software, and post-processing techniques. Also, microphone selection and placement, grounding and shielding techniques, noise reduction systems and advanced multi-track techniques.

+ 192C. Session Recording. Independent engineering of recording sessions.

* Music 220. Computer-Generated Music + 220A. Fundamentals of Computer-Generated Sound. Introduction to computer sound generation, composition, acoustics, and computer programming.

+ 220B. Techniques for Digital Sound Synthesis, Effects, and Reverberation. History of digital synthesis techniques (additive, subtractive, nonlinear, wavetable, and physical-modeling); digital effects algorithms (phasing, flanging, chorus, pitch-shifting, and vocoding); and techniques for digital reverberation.

+ 220C. Research. Research projects in composition, psychoacoustics, or signal processing.

* Music 242. Seminar: Topics in Computer Music. Various topics according to interest.

* Music 320. Introduction to Digital Signal Processing (DSP) and the Discrete Fourier Transform (DFT). Introduction to the mathematics of digital signal processing and spectrum analysis from an audio perspective. Topics: complex numbers, sinusoids, loudness scales, signal theory, the DFT, fundamental Fourier theorems, and basic Fourier pairs.

* Music 420. Applications of the Fast Fourier Transform (FFT). Spectrum analysis and signal processing using the FFT, emphasizing audio applications. Topics: FFT, cyclic and acyclic convolution, zero padding, spectrum analysis of deterministic and stochastic signals, the overlap-add and filterbank-summation methods for short-time Fourier analysis, modification, and resynthesis; transform coders, tracking sinusoidal peaks across FFT frames, and modeling time-varying spectra as sinusoids plus filtered white noise using the FFT for both analysis and resynthesis.

* Music 421. Signal Processing Methods in Musical Acoustics. Computational models of musical instruments in the wind and string families based on physically accurate mathematical models. Models are designed to capture the ``audible physics'' of musical instruments using computationally efficient algorithms and signal processing techniques. Topics: mass-spring systems, discrete-time simulation, the one-dimensional wave equation, traveling waves, wave impedance, signal energy and momentum, lumping of losses and dispersion, simulation of one-dimensional waveguides such as vibrating strings and woodwind bores, allpass techniques for tuning and stiffness simulation, scattering theory, lattice/ladder digital filter theory, and complete models of winds and strings using delay lines, scattering junctions, low-order digital filters, and nonlinear junctions implementing oscillation sources such as bow-string and reed-bore couplings. Techniques are outlined for calibrating model parameters to recordings of real instruments.

CCRMA also offers a series of summer workshops. Courses offered in 1993-94 included the following:

* Introduction to Yamaha VL Synthesizers and Algorithmic Composition in Common LISP. This course covers the basic principles and techniques of algorithmic composition. Sound synthesis as used in course examples include MIDI, the (real-time) Music Kit and (non-real-time) Common Lisp Music and Common Music Notation. Yamaha synthesizers used in the course will include the VL-1 and SY-77.

* Advanced Projects in Algorithmic Composition. A continuation of the above course, emphasis is placed on developing programming skills while working on individual projects.

* Intensive Music/Audio Digital Signal Processing and Spectral Modeling Synthesis. This course covers analysis and synthesis of music signals based on physical and spectral models.

* Music Printing with Small Computers Using SCORE. This course covers the details of the use of the SCORE software program for the creation of publication-quality music typography on PC compatible computers. Emphasis is placed on individual projects.