ECE4803B: Theory and Design of Music Synthesizers

ECE4803B: Theory and Design of Music Synthesizers

Aaron putting together the MOTM-485
Instructor: Prof.
Aaron Lanterman
Office: Centergy 5212 (often) or Bunger-Henry 323 (rarely)
Phone: 404-385-2548
Course website:

When and where: MW, 4:30-6:00, Van Leer C457 (sent via real-time
video link to GTREP)

The photo: Aaron in the beginning stages of putting together
the MOTM-485
VCF, which is based on the diode-ring Sallen-Key filter from
(in case you’re wondering, the answer is yes, I am the only prof on
my floor with a soldering iron!)

Aaron’s SDIY Pages



Lectures may be downloaded as
files. Warning: They’re pretty big (150 to 200 MB). If you find these
lectures useful, please consider making a small donation (maybe $10 or
thereabouts) to the Georgia Tech Foundation earmarked to go towards
synthesizer research; the funds will go towards parts and equipment
for student projects. Instructions for how to donate will be forthcoming.


We will draw material from numerous sources: book, articles, patents,
and particularly schematics and descriptions posted on websites. Think of
google as the main class text.

So far, I’ve drawn material from the following books (which I’d recommend
getting if you want to pursue the topic beyond this course):

  • Hal Chamberlin, Musical Applications of Microprocessors, 2nd
    Edition, Hayden, 1982; if you
    get just one book, this is THE book to get. Although it has
    “microprocessors” in the title, it has a superb section on analog circuits.
    NOS (New Old Stock – meaning old, but unused) copies are available for
    purchase from Jeff Dec ($50 + shipping); e-mail

  • Barry Klein, Electronic Music Circuits, SAM, 1982. Long out
    of print, but photocopies can be purchased directly from

Highly Tentative Outline

  • Intro: 40 Years of Music Synthesizers
  • Overview of a typical “modular” synthesizer
    • Control voltage concept; gates and triggers; signal standards
    • MS-20 demo
    • Reaktor demo
  • Voltage Controlled Oscillators (VCO)
    • Saw and Triangle Cores
    • V-to-I Exponential Conversion
    • Basic waveshaping: saw->tri recitification, tri->sin warping
  • Digital oscillators
    • Sample recording and playback; constant vs. variable D/A clock rates
    • Wavetables
    • The evils of aliasing
    • Band-limited impulse trains
  • Complex analog waveshaping circuits
    • Deadband addition (Don Buchla style)
    • Wavefolder cascade (Serge style)
  • Digital waveshaping
    • The evils of aliasing
    • Chebychev polynomials
  • Voltage Controlled Filters (VCF)
    • Analog filter topologies
      • Four-pole buffered with negative feedback
      • Four-pole unbuffered with negative feedback
      • State Variable
      • Sallen-Key
    • Variable gain/resistance techniques
      • Vactrols
      • Operational transconductance amplifiers
      • Dynamic diode resistance
    • The Moog transistor ladder filter
  • Digital emulations of analog filters
  • Additive synthesis
    • Analysis/resynthesis
  • Frequency Modulation (FM)/Phase Modulation (PM) synthesis
  • Physical modeling synthesis
    • The wave equation
    • Travelling wave solutions and waveguides
    • Excitation models: plucking, blowing, stick/slip bowing