Dr. John M. Strawn, Ph.D.


John Strawn, Ph.D., Expert Witness

(Download Resume as PDF)

Professional Profile

  • Seasoned testifying expert witness with litigation experience (patent, copyright, trade secret, class action), skilled at explaining complex ideas to attorneys and juries (see separate list of expert witness litigation assignments)
  • Several decades of involvement in software, digital audio, digital music, digital signal processing, and processor architecture.
  • Successful independent software consultant in high-level languages and assembly language.
  • Stanford Ph.D.
  • Former Fulbright Scholar.
  • Prolific author.
  • Experienced manager with long-range research and development experience.
  • Facile with foreign languages and working with people from outside the USA.

Professional Experience

S Systems Inc. (Owner, 1992-present)  Full-time independent consultant:
  • Testifying expert witness in patent and copyright litigation relating to software and source code, digital devices, processor architecture, media, compression, signal processing and client/server interactions. A list of expert witness experience is available separately.
  • Programming hand-crafted audio and music software for signal processing, written in C, C++, Java, and especially assembler for digital signal processing chips. A list of software projects is available separately.
Yamaha Music Technologies USA (1989-1991: President; 1987-1989: Vice President)  Helped establish and manage a nine-person Ph.D.-level research group, including site search, architectural design, construction, move-in, and hiring.  Conducted original research on electronic musical instruments, software, user interfaces, micromachining, networking, and recent technological developments. Extensive experience designing scientific, engineering, and musical object-oriented applications, especially C++ (UNIX). A list of patents is available below. Research on Yamaha’s Vocaloid started in this group.
S Systems Inc. (Owner, 1986-1988)  This was my first stint as a consultant. A list of software projects is available separately.
Lucasfilm/Droid Works (Programmer, 1985-1986)  Full-time programming experience as software engineer, designing signal-processing modules and writing (96-bit VLIW) microcode for the ASP/SoundDroid developed by James A. Moorer. Experience in audio and video post-production. Extensive work in C (Unix). Another six months full-time experience writing tightly packed assembly code for the TI TMS32010 DSP chip, especially for a two-channel hard-disk audio record playback unit that played without bugs on the exhibition floor of the National Association of Broadcasters convention, 1986 (source code and documentation).
Stanford University (Doctoral Student, 1976-1985)  Nine years programming experience developing code in high-level languages (Algol, Fortran, SAIL) and PDP-10 assembler for musical and audio signal processing applications during doctoral thesis work. My Ph.D. dissertation (Modeling Musical Transitions, 1985) involved original published research in spline fitting (source code), a 30,000-line two- and three-dimensional graphical editor for waveforms and spectra (documentation, sample source code), implementation (with John Gordon) of the short-time Fourier transform (book chapter), device drivers, and libraries for graphic user interfaces. Also part-time consulting work:
  • SRI International: FORTRAN for mechanical engineering.
  • Mattel Electronics: music in consumer electronic toys.
  • IntelliGenetics: ALGOL-like code for biotechnology.
  • Digital Keyboards: product specification for GDS and Synergy Synthesizers; write GDS manual and Synergy manual.
Revox (Summer intern, 1972; Long Island, NY)  Solder cables, write German- and Dutch-English translations, manufacture PC boards, assemble hardware.

Education and Training

Stanford University

Ph.D., CCRMA, 1985.

Advisor: John Chowning. Graduate course work in music, signal processing, computer architecture, assembly-language coding, digital audio, acoustics, psychoacoustics, and digital hardware. Software development experience listed above. For the Ph.D. dissertation (Modeling Musical Transitions, 1985) I analyzed articulations and transitions between notes in digitized monophonic musical instrument recordings using the short-time Fourier transform.

IBM Thomas Watson Foundation

Grant to study electronic music, Tokyo, Japan, 1976.

Live performances on piano and Roland System 700 analog synthesizer.
Also travel through Turkey, Iran, Afghanistan, Pakistan, India, Thailand, and Hong Kong.

Fulbright Scholar, Technical University Berlin

Berlin, Germany, 1973-74, renewed 1974-75.

Graduate-level course work in music theory/history, audio engineering, analog studio electronics, cybernetics, control theory, coding theory, Japanese; all course work in German. Extensive recording studio and live concert sound reinforcement experience, including Berlin Jazz Festival and the Metamusik Festival (program).  PDP-11 and PDP-8 assembler and machine language. Travel throughout Europe.


B. Mus., 1973.

Double degree in organ and music theory. Programming in FORTRAN (source code listing), Basic, MUSIC V on an IBM 360 mainframe. Experience with analog synthesizers and digital music synthesis. Exchange semester, University of Hamburg, Germany, 1971, course work in German literature and psychology.

Expert Witness and Litigation Experience

Summary:  19 depositions to date, 3 times testimony at trial, 10 declarations filed in 17 Inter Partes Reviews (IPRs).  Patent litigation, ITC investigations, Inter Partes Reviews, USPTO declarations, class action litigation, trade secret litigation, copyright litigation involving software.  Expert reports, declarations, prior art research and analysis, infringement analysis (e.g., analyze devices, documents; source code analysis, source code comparison), claim charts, tutorials, Markman hearings.  Technical areas include software and source code; computers, laptops, cell phones, mobile devices, handheld devices (e.g. medical); processor architecture; user interfaces; media: audio, music, speech, video; compression (e.g., MPEG, MP3); digital signal processing, mathematics, algorithms; file downloading, file streaming, client/server; protocols such as internet protocol (IP); video games. A list of expert witness assignments including depositions and testimony is available separately.

Consulting Experience

Summary: Software in high-level languages (e.g. C, C++, Java, Fortran), assembly language (digital signal processors, embedded processors, custom processors), and Matlab, for signal processing applications, often related to audio and music. Related projects such as processor design, mergers and acquisitions, feasibility studies, and standards work. A list of consulting projects is available separately.


  • Seasoned testifying expert witness with litigation experience (patent, copyright, trade secret, class action), skilled at explaining complex ideas to attorneys and juries (see separate list of expert witness litigation assignments)
  • Software analysis for litigation including patent, copyright, trade secret, software theft.
  • Assembler, object-oriented, C, C++,  HTML, XML, Java, Javascript, SQL.
  • Implement/optimize signal processing algorithms: Fourier transform (FFT), discrete cosine transform (DCT), DTMF, speech synthesis.
  • Port/optimize audio compression algorithms: AC-3, MP-3, AAC.
  • Implement audio algorithms: reverberator, pitch shifter, sample rate converter, compressor, filter, flanger, 3-d audio (Dolby surround), dither.
  • Implement music synthesis (additive, physical modeling, wavetable, FM).
  • Create bug-free software from academic signal processing research.
  • Work in floating- and fixed-point math.
  • Extensive experience optimizing code in assembler
  • PC, Mac, Unix.
  • DSP processor architectures: Motorola 56000, 56300, and 56800 families; TI TMS320C10 and TMS320C54 family; Code Composer Studio; Analog Devices 21xx family and TigerSharc; VLIW; custom processors; I learn new processor architectures quickly.
  • Embedded processors: Hitachi SH-DSP, SH3-DSP, SH-4, and SH-5; ARM7/ARM9; configurable processors (Tensilica).
  • Processor architecture.
  • Debugging hardware prototypes.
  • Media networks, such as AES/EBU (IEC 60958), IEEE-1394/FireWire, AV/C, 61883, mLan, and others.
  • File downloading.
  • Practical audio experience in live sound and in studios.
  • Functionally bilingual in German; able to read French, Dutch; some Japanese


I was co-inventor on US5,569,871, titled “Musical tone generating apparatus employing microresonator array” (USPTO, pdf, 1996) involving micromachining.

When I was manager of an R&D group for Yamaha, the group was trained by a crack patent attorney on the theory and practice of obtaining  patents. The group was awarded several patents for which I supervised the work:

5,245,130 (USPTO, pdf)  1993  Polyphonic breath controlled electronic musical instrument
5,288,938 (USPTO, pdf)  1994  Method and apparatus for controlling electronic tone generation in accordance with a detected type of performance gesture
5,386,568 (USPTO, pdf)  1995  Apparatus and method for linking software modules
5,422,956 (USPTO, pdf)  1995  Sound parameter controller for use with a microphone
5,536,902 (USPTO, pdf)  1996  Method of and apparatus for analyzing and synthesizing a sound by extracting and controlling a sound parameter
5,541,358 (USPTO, pdf)  1996  Position-based controller for electronic musical instrument

Teaching Appointments

Lecturer, Department of Music & Entertainment Industry Studies, College of Arts & Media, University of Colorado at Denver, 2003-2008. Teach special topics course on audio data compression to upper-level undergraduate and graduate students. (2008 slides; 2008 handouts).

Major Publications

  • “Approximation and Syntactic Analysis of Amplitude and Frequency Functions for Digital Sound Synthesis.” Computer Music Journal 4(3):3-22, 1980. (pdfsource code).
  • Modeling Musical Transitions. Ph.D. Thesis, Stanford University, 1985. 243 pp. (pdf).
  • (with C. Roads). Foundations of Computer Music. MIT Press, 1985. 600 pp.
  • Digital Audio Engineering: An Anthology. Madison, WI: A-R Editions, 1985. 144 pp.
  • Digital Audio Signal Processing: An Anthology. Madison: A-R Editions, 1985. 283 pp. An early version of the phase vocoder chapter is available here and an early version of Julius Smith’s introductory filter chapter is available here.
  • “Orchestral Instruments: Analysis of Performed Transitions.” Journal of the Audio Engineering Society 34(11):867-80, 1986. (pdf).
  • “Editing Time-varying Spectra.” Journal of the Audio Engineering Society 35(5):337-51, 1987. (pdf, editor documentation, editor source code).
  • “Analysis and Synthesis of Musical Transitions Using the Discrete Short-time Fourier Transform.” Journal of the Audio Engineering Society 35(1/2):3-14, 1987. (pdf).
  • “Implementing Table Lookup Oscillators for Music with the Motorola DSP56000 Family.” Presented at the 85th Convention of the AES, 1988. Preprint No. 2716. (PDF with source code).
  • “Digital Audio Representation and Processing.” Multimedia Systems, edited by John F. Koegel. ACM and Addison-Wesley, 1993.
  • “Technological Change: The challenge to the audio and music industries” (written version of 1996 AES convention keynote address). Journal of the Audio Engineering Society, March 1997. (pdf).
  • “AES White Paper: Networking Audio and Music using Internet2 and Next Generation Internet Capabilities.” (pdf; with James Grunke, Ben Novak, Bruce Pennycook, Zack Settel, Phil Wiser, and Wieslaw Woszczyk). Journal of the Audio Engineering Society 47(4):300-310, April 1999. Presented (with Betsy Cohen, Marina Bosi) to White House National Economic Council, December 1998. Featured in Pro Sound News, January 1999, 67-72, and Billboard 2/27/99, p. 43.
  • “Playing with Fire” (on audio networking over 1394, with Yamaha’s Mike Overlin), Electronic Musician, May 2003, pp. 31-38. (pdf).
  • “Basics of Digital Sound, Part One: Digital Recording.” Keyboard, March 1981, pp. 16-20. (pdf). “Part Two: Digital Synthesis.” Keyboard, June 1981, pp. 18-22. (pdf).
  • “Research on Timbre and Musical Contexts at CCRMA.” International Computer Music Conference (ICMC), Venice, Italy, September 27 – October 1, 1982, pp. 437-465. (pdf).
  • “Computer und Musik in den USA” (“Computers and Music in the USA”). Oesterreichische Musikzeitschrift, September, 1984, pp. 459-462. (pdf).
  • More publications to follow.
  • See also Presentations, below.


  • (with Perkins Coie partner Thomas Millikan). “What Happens in a Patent Lawsuit” (introduction to the stages of patent litigation). DesignCon 2018; Audio Engineering Society Convention 2017 (program, slides), 2016 (program).
  • Four-hour presentation on audio compression, given first at Embedded Processor Forum, June, 2000; revised to include audio and music, presented at Microprocessor Forum, October 2000; revised with emphasis on streaming audio and presented at Embedded Processor Forum, June, 2001. (For client BDTI).
  • “Tutorial on Audio Compression.” AES Convention, Paris, 2006 (program, slides).
  • “Assembly Language Programming: Street Smarts from Object Oriented Programming.” AES Convention, New York, 2005 (program, slides).
  • “Pro Audio and Music: Implications for Home Networks.” 1394 Trade Association, October 2003 (slides).
  • “Introduction to mLAN” (with Yamaha’s Mike Overlin), November 2003 (slides)
  • “DSP Chips for Audio Applications.” DSPx, 1994 (program).
  • Technical presentations and session chair at various conferences such as Audio Engineering Society, Acoustical Society of America, DSP World.
  • “Digital Rock and Roll; Implementation of the SoundDroid Fine Editor.” 1986 IEEE ASSP Workshop On Applications Of Signal Processing To Audio And Acoustics, Mohonk, NY. (pdf, conference website).
  • “Orchestra Instruments: Analysis of Performed Transitions.” Proceedings, International Computer Music Conference, 1985, pp. 347-353. (pdf, full proceedings).
  • “Graphics-based Methods in Digital Sound Editing.” Proceedings, Nicograph ’83 (Tokyo), pp. 49-54 (pdf).
  • “eMerge: toward a Knowledge-Based Spectral Editor.” Proceedings, International Computer Music Conference, 1983, pp. 54-55. (pdf, full proceedings, editor documentation, editor source code).
  • “Spectra and Timbre.” Proceedings, International Computer Music Conference, 1983, p. 56. (pdf, full proceedings).
  • “Research on Timbre and Musical Contexts at CCRMA.” Proceedings, International Computer Music Conference, Venice, Italy, 1982, pp. 437-465. (pdf, full proceedings).
  • “Approximation and Syntactic Analysis of Amplitude and Frequency Functions for Digital Sound Synthesis.” Proceedings, International Computer Music Conference, 1980, pp. 116-137. (pdf, full proceedings , source code).

Professional Associations and Achievements

Further Qualifications

Functionally bilingual in German. Reading ability in French, Dutch. Some experience with Spanish, Italian, Japanese, Latin. Extensive experience travelling abroad and communicating with foreigners. A summary of foreign language experience and list of translations is available separately.

Other Activities

I currently enjoy spending time with my family, hiking, and weightlifting. In earlier years I have especially enjoyed travel, aikido, operating a Maerklin Z-gauge model railroad, performing a wide variety of folk and classical music, and attending musical events. Member of Toy Train Operating Society of America.


Full vita and references from industry, academia, and lawfirms available on request.

For more information, contact (Dr.) John Strawn.