Instructor: Prof.
Aaron Lanterman
Office: Centergy 5212 (often) or Bunger-Henry 323 (rarely)
Phone: 404-385-2548
E-mail:
lanterma@ece.gatech.edu
Course website: users.ece.gatech.edu/~lanterma/ece4803
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
the
Yamaha
GX-1 (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
-
Synth
DIY Datasheet and Ap Note Collection -
Music synthesis
patents collection, with some brief commentary -
Current
modular synth manufacturers – look through these to get ideas for your
own new designs, ideas for packaging, etc.
Homeworks
- Homework 1 (due 1/30)
- Homework 2 (due 2/8)
- Homework 3 (originaly due 2/22,
but extended to 5 PM – can slip under my Bunger Henry 323 office door –
I’ll come grab them before heading out for the weekend) - Homework 4
- Homework 5 (due 3/15)
Lectures
Lectures may be downloaded as
RealPlayer
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.
- 1/9 –
40 Years of Music Synthesis, Part I (Moog/Buchla up to DX7) - 1/11 – 40 years of Music Synthesis, Part II
(DX7 and after) - 1/18 –
Meet the Korg MS-20, a typical analog semimodular synth - 1/23 –
Op amp review, part I (resistive circuits) - 1/25 –
Overview of Music Technology Projects – guest lecture by
Gil Weinberg - 1/30 –
Op amp review, part II (first-order RC circuits) - 2/1 –
Operational Transconductance Amplifiers (OTA)
(with VCA example), Norton
op amps - 2/6 –
Voltage Controlled Oscillators (VCO): Sawtooth Core;
visit to
the ECE4006 labs - 2/8 –
Voltage
Controlled Oscillators (VCO): Triangle Core; distribution
of the MOTM kits - 2/13 –
Analog Waveshaping, Part I: saw->pulse, saw->triangle,
triangle->sine, Serge wave multiplier demo
Suggested references:- R. Williams,
Triangle to Sine Conversion with OTAs - M.H. Miller,
“Triangle
to Sine Conversion (Nonlinear
Function Fitting)”, ECE414 Notes - R.G. Meyer, W.M.C. Sansen, S. Lui, S. Peeters,
“The Differential Pair as a Triangle-Sine Wave Converter”,
IEEE J. of
Solid-State Circuits, June 1976, pp. 418-420. - G. Klein,
Accurate Triangle-Sine Converter - Far-out ideas:
- H. Hassan, FET
Differential Amplifier as a Tri-Wave to Sine Converter,
Proc. 36th Southeastern Symposium on System Theory, 2004, pp. 427-430 - Z. Tang, O. Ishizuka, H. Matsumoto,
MOS Triangle-to-Sine Wave Convertor Based on
Subthreshold Operation, Electronics Letters,
Vo. 26, No. 23, Nov. 8, 1990, pp. 1983-1985.
- H. Hassan, FET
- R. Williams,
- 2/15 –
Analog Waveshaping, Part II: Ken Stone’s wavefolder,
Buchla’s diodeless deadband circuit, Buchla’s timbre generator
References
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
jdec@mindspring.com - Barry Klein, Electronic Music Circuits, SAM, 1982. Long out
of print, but photocopies can be purchased directly from
barry.l.klein@wdc.com
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
- Analog filter topologies
- 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