Buchla 400

Model 404A (1982) with transit case, monitor and 408 storage card.

Part One : Overview

In 1981, development began on the Buchla 400: a culmination of the concepts pioneered in the previous designs for the Model 500, Series 300, and Touché. The Buchla 400 (or “400”) used a microprocessor and custom software to control an intricate array of internal electronics. It was part computer, part performance instrument, part composition ecosystem—introducing many distinct means for exploring the unique potential of computer-controlled sound generation.

The 400 was a self-contained, six-voice polyphonic, multi-timbral instrument which continued Donald Buchla's trend of conceptual refinement and increasing functional density. Many aspects of the 400 bear resemblance to his prior designs, such as the emphasis on frequency modulation and nonlinear wave shaping techniques as a primary focus for sound manipulation. Unlike previous designs, it added a 12dB/oct resonant lowpass filter for each voice, as well as an 8 stage stereo phase shifter on the final output—further expanding the 400’s sonic vocabulary. Of course, the 400 continued Buchla's explorations in human-machine interaction: it provided a platform for practice-led investigation into unconventional linkages between user input and sonic response.

New to the 400—and revolutionary at the time—was a graphical user interface on a color video display. The 400's computer and its support for GUIs enabled the creation of several high-level, composer-friendly computer “languages”: programs which each provided distinct means of addressing the instrument's internal sound-generating electronics. These included the possibilities for musical score editing, algorithmic sequencing, real-time performance, and more.

System Block Diagram

Over the course of its lifetime, three primary languages were offered for the 400, all developed by Donald Buchla and his long-time collaborator, programmer D. N. Lynx Crowe—who had worked previously on the computer and software design for the 500 and 300 Series instruments. The 400 introduced the earliest versions of MIDAS (Musical Instrument Definition and Scoring), a language centered around graphical specification of instrument parameters as well as a musical score editor. (This language concept later appeared in a new form in the Buchla 700.) The 400 also offered new versions of the PATCH software, developing directly on conceptual frameworks that began with the 500 in the early 1970s. By design, the 400 could also support user-developed operating systems, which could be programmed using a slightly modified FORTH derivative called MUSICFORTH.

So, despite the fact that the 400’s internal audio structure was essentially fixed/constant, its potential uses were vast. That is to say, though the 400 was always a six-voice instrument with a specific voice structure, it was up to the user to determine how they wanted to interact with that structure, and therefore, which language best suited their immediate goals. Once they had settled on their preferred approach, they could simply load the desired program from tape or disk at any point. And, if no extant software was available to solve their specific musical problems, they were permitted (even encouraged) to develop their own.

Offering an extensible computer backend and multiple programs for addressing a built-in, flexible sound generation engine, we can think of the 400 as being conceptually similar to contemporary designs such as the New England Digital Synclavier or Fairlight CMI Computer Musical Instrument. Developed before the introduction of MIDI, it offered SMPTE standard synchronization (useful for syncing to tape and film). Additionally, a host of control voltage and timing pulse I/O enabled bidirectional communication with control-voltage-capable devices. These considerations made the 400 a viable candidate to act as the center of a professional studio. So, to look at it purely as a polyphonic synthesizer (in the manner of the Prophet-5 et al.) is not entirely apt; instead, one can look at the 400 as a prototypical digital audio workstation.

As an aside, this perspective is perhaps intensified by noting that the 400 can also be seen as a general-purpose computer with an integrated synthesizer engine. That is to say, while the 400 was designed primarily for the purpose of composing and performing music, it was capable of running third-party programs and included provisions for printing, connection to external terminals, and system expansion via the IEEE-696 (S-100) bus. Product brochures for the 400 indicate that “the instrument can be expanded into a flexible computer system appropriate to applications such as word processing, network communications or program development.” You can’t do your taxes on your Prophet-5.

In 1983, the model 406 was added to the 400 Series lineup, adding a mechanical, weighted, velocity-sensitive black and white keyboard with polyphonic pressure sensing in place of the 404’s array of capacitive touch plates. At the request of Kimball Electronics—who purchased the 400 design in 1984—Buchla and Crowe eventually developed a new language called CHOPS, which offered a more immediate, user-friendly playing experience than MIDAS or PATCH. Among other new features, CHOPS facilitated the definition of keyboard splits, layers, and new modes and methods of sequencing not found in the earlier Series 400 programs.

Designer Donald Buchla at home with his latest creation (1982)

Between 1982 and 1985, close to forty Series 400 instruments were assembled and sold. Systems could be found in studios and institutions across North America and Europe.

The 400 was produced in larger quantities than all of Buchla's previous computerized system designs combined. It underwent the most extensive refinement and debugging of any hybrid Buchla instrument. It is stable and serviceable, and yet today, it is still little-known and often misunderstood.

Recently, the Buchla Archives has been deep in the midst of 400 research and restorations. We’re excited to share more about it soon—explanations of its unique sonic features, overviews of its various languages, and more.

RG/RS