1982 Buchla 400
The 400’s unique architecture features three computers, each of a different nature, and each optimized to its particular function.
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.
Multilevel extensibility is a fundamental aspect of the 400’s design.
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.
Multifunctional in nature, the Buchla 400 is designed to serve the needs of composers, performers, educators, and listeners.
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.This is an expressive instrument created by musicians for musicians.
Directed by Don Buchla, the 400 development team included 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 designed instrumentation and music for a hundred piece electronic orchestra.
SERIES 400 PRODUCTS
Complete with self-contained IEEE-696 standard computer, this is the system for the musician that wants an instrument “to go”. It includes a comprehensive front panel, an exotic touch sensitive keyboard, a sophisticated character and graphics display facility, and lots of potent software. For editing and information storage you’ll need a standard video monitor and a cassette tape recorder of reasonable quality.
A general purpose development system that includes the above-mentioned computer-based instrument and adds dual 8″ floppy disks, controller, terminal, printer and video display. Also included in complete and thoroughly documented source code and a manual describing the intricacies of MIDAS and musicFORTH, the 400 series operational languages.
Recommended for the musician on the road, this sturdy, foam-lined fiberglass case accommodates system 404A. It’s manufactured by Thermodyne International, and will outperform and outlast your standard road cases by a country mile.
Small PROM-based cards for storing instrument configurations, enabling instant recall of tunings, waveshape tables and instrument definitions. Each 2″ x 2″ card stores up to 24 instrument definitions, 24 waveshape tables and 4 tuning tables.
Control Voltage Inputs
(9 total) pitch / timbre / modulation input / filter cutoff frequency / gate level / 4 software defined inputs / connectors: standard banana / range: 0 to 10 volts
(5 total) forward frame pulse / reverse frame pulse / 3 software defined inputs / connectors: standard banana / threshold: 1.5 volts
Control Voltage Outputs
(10 total) all functions software defined / connectors: standard banana / range: 0 to 10 volts
(5 total) forward frame pulse / reverse frame pulse / 3 software defined outputs / connectors: standard banana / level: 10 volts or TTL / duration: .001 seconds
(8 total) 2 channel stereophonic bus; 1/4″ phone connectors; 200 ohms impedance / 6 individual voice outputs; miniphone connectors; 600 ohms impedance / all audio output levels are 1.2 volts rms.
video out: BNC connector, 75 ohms, composite signal, for use with standard video monitor / tape in/out: miniphone connectors, 1.2v rms, for use with quality audio cassette recorder / terminal/printer: RS232 with selectable baud rate, for user access to internal computer.
voltage: 110 or 220 VAC Power: 75 watts maximum
weight: 15 kg (33 pounds) dimensions: 68 cm x 40.5 cm x 12.5 cm
Circuitry and Architecture
supervisory control and data handling: internal IEEE-696 based general purpose digital computer / function generation and input correlation: 64 channel multiple arbitrary function generator / signal generation: pipelined, multiplexed, 6 voice digital oscillator with PROM based microcode / signal processing (gating, filtering, phasing and location): voltage-controlled analog circuitry / primary editing inputs: 24 touch activated keys, pressure sensitive joysticks, sealed pushbutton switches / primary performance inputs: 100 programmable touch activated keys, pressure sensitive joystick, accessories / software: MIDAS, a PROM resident, instrument definition, performance and scoring language