electronic musical instrument
description and specifications
SERVING AS THE NERVE CENTER OF THE INSTRUMENT is a general purpose digital computer. Programmed to perform user communication, data handling, and supervisory control, this "host" computer may be reprogrammed to realize future musical needs or alternative instrumental concepts.
Receiving instructions and data from the host, a second computer (called the multiple arbitrary function generator), directs the progress of 64 acoustic parameters, each with a time resolution of 1/1000 of a second. This facility enables precise specification of complex sonic detail and offers expanded possibilities for expressive articulation.
A third computer, this one a pipeline digital signal generator, produces the instrument's six voices. Built into this computer are unusually powerful algorithms for timbre generation, including frequency modulation, waveshape interpolation and timbre modulation (unique to the Buchla, this technique significantly augments the electronic vocabulary).
Gating and filtering are performed by voltage-controlled analog circuitry, providing a dynamic range exceeding 90 dB. Specialized phasing and location circuitry provides unusual depth and imaging in the resultant acoustic field and enables independent location of each voice in stereo space.
AN ARRAY OF CONTROL VOLTAGE INPUTS AND OUTPUTS permits the instrument's powerful control structure to interact with a variety of auxiliary equipment. 200 series modules may be used to augment the 400 for specialized applications, ranging from biofeedback control to signal processing of accompanying instruments. Pulse interconnections allow synchronization with external events, additional instruments, or other media; and individual voice outputs facilitate post-processing of signals.
To further assure ease of expansion of resources and capabilities, the internal processor incorporates the industry standard IEEE-696 bus. By adding readily available plug-in cards, the instrument can be expanded into flexible computer system appropriate to applications such as word processing, network communications or program development.
The instrument's operational language (MIDAS) is programmed in musicFORTH, a high level language distinguished by its transportability, extensibility and ease of user access. MIDAS presently combines a real-time score editor with a comprehensive instrument definer. New versions of MIDAS will add new capabilities, keeping the Buchla 400 a growing and vital instrument with ever-expanding resources.
OF PARTICULAR INTEREST TO THE COMPOSER is a musically sophisticated score editor that functions in real time. Six orchestrally differentiated voices can simultaneously be displayed, auditioned, and edited. Musical data is efficiently presented with linear-time notation and a high-resolution graphic display. Instrument definitions, dynamics, tempi, registration, and tunings are programmable, and a menu-driven editor provides for sectional labeling, recall, inserts, merges, copies and jumps. The instrument can decode, display, and track a SMPTE time code signal, facilitating film, video, and multitrack composition.
THE PERFORMER CONCOCTS HIS SONIC FEASTS from an array of timbral ingredients unprecedented in musical cuisine. Dynamic waveshaping techniques, multiple complex envelope generation, and advanced concepts of instrument definition provide an extensive electronic vocabulary. A specialized touch sensitive keyboard can be organized in traditional or nontraditional fashions, can be tuned to any imaginable scale, and responds to the subtlest of musical gestures. Pressure-sensitive joysticks, control voltage interconnections, and analog modifiers further extend the possibilities.
AS AN EDUCATIONAL TOOL, the Buchla 400 is unusually comprehensive. With an architecture capable of implementing a variety of synthesis techniques, the intricacies of frequency modulation, timbre modulation and non-linear waveshaping can be effectively presented. Fast real-time graphic displays of waveshape tables and parametric envelopes enable experimentation with the elements of musical structure. Tuning systems, principles of orchestration, and other aspects of theory can be explored, and sophisticated high level software facilitates the development of new musical languages and compositional algorithms.
FOR THE LISTENER, who is the final link in the musical chain, the Buchla 400 offers some unusual possibilities. With the capability of storing complete scores on cassette tape or plug-in cards, the instrument serves as an idealized playback medium, recreating the composer's intent with uncompromised fidelity. If he chooses, the listener can display a score and interact with it at any level, from modifying balances, tempi, or instrumentation, to completely reconfiguring a composition. Thus the listener may abandon his role of passive consumer, and become a creative producer of the acoustic experience.
DIRECTED BY DON BUCHLA, the 400 development team includes composers and performers as well as experts in man-machine interface, electronic design, computer science, and psycho-acoustics. Mr. Buchla's professional background includes space biophysics research, multimedia composition, the performance of avant garde and traditional music and the design of both acoustic and electronic instruments. As a Guggenheim fellow, he recently completed research in interactive performance-oriented computer music languages, and as an NEA fellow, he is currently designing instrumentation and music for a hundred piece electronic orchestra.