POD & PODX* System Chronology

Institute of Sonology, Utrecht


PDP-15 version, programs POD4, POD5 & POD6

(with monophonic real-time synthesis: fixed waveform, amplitude modulation, frequency modulation)

Detailed documentation Sonological Reports #2; published summary in Interface

* Note: POD stands for Poisson Distribution which was the original stochastic probability distribution (for random isolated events) that was used to determine the placement of sonic events in the original sequence of programs; when the DMX-1000 was added in 1982 (see below), the X was added to the name.


Simon Fraser University, Vancouver


Hewlett Packard 2116 version, programs POD6, PDFIL, MERGE, POD7

(with monophonic real-time FM synthesis and 1976-78, polyphonic non-realtime FM synthesis)

Computer Music Journal article; IEEE article


PDP 11/34 version, same programs plus PDMSK

(with monophonic real-time synthesis and polyphonic non-realtime FM synthesis with the Varian computer)


LSI 11/23 version established in the Centre for the Arts, SFU


LSI 11/23 version with DMX-1000, PODX system with polyphonic real-time programs
POD6X, POD7X, PDFILX, MERGE, CONDUC, FUNC, PDMSKX, PLOTX, and non-realtime program POD7

Computer Music Journal article on PODX

Follow the detailed evolution of the PODX software, as reported to the users as PODX News (1983-1996)

Martin Gotfrit with the LSI 11/23 & DMX-1000, ca. 1982

Watch a short video introduction to the PODX hardware system in 2013


Real-time Granular Synthesis program added (GSX) using the DMX microprogrammable architecture with this synthesis code
Computer Music Journal article

Watch a video demonstration of real-time granular synthesis with the GSX program and the DMX-1000 in 2013


Real-time Granulated Sampled Sound added to granular synthesis (GSAMX)


Initial work on Motorola DSP 56001 board to be controlled by an Atari computer


Digisound-16 converter added to PODX enabling 16-bit conversion of samples to hard disk (at sampling rates between 19 and 32 kHz); granulation and time stretching incorporated
Computer Music Journal article


Demo of "Quintessence Box" real-time granular synthesis using DSP 56001 at ICMC 91, Montreal


Quintessence Box incorporating granular time stretching installed in SFU studios; prototype of a multiple-DSP board designed by Harmonic Functions, Burnaby


DM-8 box for computer-controlled diffusion demonstrated at ICMC 95 and installed in the Sonic Research Studio at SFU; Karplus-Strong digital resonators (single and double, in mono or stereo) added to the real-time signal processing modules during disk playback, in addition to reverb, stereo delay, comb filter, multi-comb filters, high and low-pass filters


PODX system "retired" to the author's private studio where it continued to be compositionally productive using the DA-88 8-track recorder


Audiobox (16x16 matrix mixer) added to the system for computer-controlled diffusion

Harmonic Functionsí TiMax2 matrix mixer, marketed by Outboard Inc (UK), added to the system for computer-controlled diffusion
Consult the list of publications and recent papers for various compositional documentations

Michael Clarke and Frederic Dufeu from Huddersfield visit the system to document it as part of their TACEM Project which includes a detailed analysis and re-creation of Riverrun. This work was published as Inside Computer Music, Oxford University Press, 2020. Several videos, as included here, were made of the system in operation. Shortly thereafter, various hardware problems emerged that could not be fixed and the system essentially was no longer usable. After 31 years of productivity (and a previous 10 years of its predecessor, the POD system), R.I.P. PODX!
List of works realized with the POD and PODX systems

Octophonic work catalogue

Note: More detailed analyses of pieces realized with the system are included in the composer's HTML Documentation as part of the WSP Database (contact Barry at truax@sfu.ca for a guest password)


B. Truax, "Discovering Inner Complexity: Time-shifting and Transposition with a Real-time Granulation Technique", Computer Music Journal, 18(2), 1994, pp. 38-48 (sound sheet examples in 18(1)).

B. Truax, "Real-time Granular Synthesis with a Digital Signal Processor", Computer Music Journal, 12(2), 1988, pp.14-26.

B. Truax, "The PODX System: Interactive Compositional Software for the DMX-1000", Computer Music Journal, 9(1), 1985.

B. Truax, "Computer Music Composition: The Polyphonic POD System", IEEE Computer, 11(8), 1978.

B. Truax, "The POD System of Interactive Composition Programs", Computer Music Journal, 1(3), 1977, pp. 30-39.

B. Truax, "Some Programs for Real-time Computer Synthesis and Composition", Interface, 2, 1973.

B. Truax, "The Computer Composition -- Sound Synthesis Programs POD4, POD5 and POD6", Sonological Reports, No. 2, Utrecht State University, Institute of Sonology, 1973.