PROGRESS REPORT ON THE RADIO BATON AND CONDUCTOR PROGRAM

Max V. Mathews Professor of Music (Research)

A processor board with an Intel 80C186 embedded computer has been added to the Radio Baton. The Conductor Program runs entirely in this board and all real-time computing required for a performance is done on this board. All communication with the Radio Baton is done via MIDI, the principal messages being scores that are down loaded from an external source into the 80C186 and note on and off commands sent from the 80C186 to a synthesizer.

The 80C186 board was designed and fabricated by Tom Oberheim at Marian Systems, Lafayette California. Oberheim is in the process of designing a production version of the entire Radio Baton which will be commercially available.

In the most used present configuration, a control computer, which can either be a Macintosh or a PC, sends scores and commands to the 80C186 board via MIDI characters. The 80C186 in turn transmits standard MIDI codes to a synthesizer which produces the desired sounds. Usually a MIDI cable is connected from the synthesizer thru back to the control computer so that the 80C186 can send messages back to the control computer. However the Radio Baton can also be used as a control device with programs such as Max Patcher where the 80C186 communicates directly with the Max Patcher computer via MIDI, and the synthesizer is connected to the Max Patcher computer via a separate MIDI channel.

The Conductor Program, various improvisation Programs (Runs, Space, etc), and the Max Patcher control program are all burned into an EPROM in the 80C186 board. The EPROM programs are developed on a PC writing in the C language (Microsoft C). New programs can be compiled and tested on the PC before they are burned into EPROMS. This has proven to be a very effective and inexpensive program development environment.

The Max Patcher interface was developed in collaboration with Andy Schloss at the University of Victoria and David Jaffe at CCRMA. It allows a control computer to poll the Radio Baton at any instant in time and obtain the XYZ coordinates of each baton (transmitted via MIDI). The Radio Baton can independently send "whack'' information to the control computer each time it is hit. The whack information includes the XY coordinates of the hit and the baton velocity of the hit. This combined polling-whacking strategy was selected to give the control computer instantaneous information about whacks and to avoid saturating the MIDI channel with continuous XYZ data.

The Conductor Program has been extended so that it can play standard MIDI files (type 0). In this mode, a header score is written as a Conductor Program score. The header score assigns the expressive functions of the batons and does other setup functions that are not accommodated by MIDI files. In the MIDI file, one MIDI channel is preempted for the beating baton. Notes in this channel are not played, but rather the beginning of each note indicated the location of a baton beat in the score.

Two control programs for the Radio Baton are available, BAT for the PC written by myself, and RADIO-MAC for the Macintosh written by Steven Berkley at Dartmouth College. Both programs are completely identical as far as scores are concerned and in fact over 90 percent of the code for the score compiler part of the two programs is identical. Both programs are written in the C language, and the common part is in ANSI C. The PC programs use Microsoft C and the Macintosh programs use Lightspeed C.

The control programs also include synthesizer library facilities which allow synthesizer voicing files to be stored, and to be sent to and from any synthesizer that can receive and transmit MIDI system exclusive voicing files.

About 20 prototype copies of the Radio Baton now exist. In addition to the batons at CCRMA, batons are at Jon Appleton's studio at Dartmouth; at Richard Boulanger's studio at the Berklee College of Music; at Josefina Bosch's studio in New York City (cabaret music); at Johannes Goebel's Institut f_rMusik und Akustik at ZKM, in Karlsruhe Germany; at Francisco Kropfl's LIPM studio in Buenos Aires; at Andre Smirnov's Theremin center in Moscow; at David Wessel's CNMAT center at Berkeley; at Andy Schloss's studio at the University of Victoria; at Jean-Claude Risset's Lab de Mechanique et d'Acoustique at CNRS in Marseille; at Johan Sundberg's laboratory at the KTH, Stockholm; at SoundDesigner Studio in New York City (theatre sound); and at the Children's Discovery Museum in San Jose.

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