ECE4893A: Electronics for Music Synthesis (Spring 2008)
Instructor: Prof.
Aaron Lanterman
Office: Centergy 5212 (but I’m rarely there)
Phone: 404-385-2548
E-mail:
lanterma@ece.gatech.edu (best
way to reach me)
Course website: users.ece.gatech.edu/~lanterma/ems
When and where: TuTh, 12:05-1:25, Van Leer C341
The photo: Xavier, Aaron, and Christine showing off Xavier+Christine’s
design for a voltage-controlled phaser (from Spring 2006)
(Note: I often abbreviate the class title as “EMS.” This usage of “EMS”
should not be confused with
“EMS” as in Electronic Music
Studios, the makers of many classic synthesizers such as the Synthis.)
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
- Grades will be based on a series of written homeworks, a quiz that
will be weighted the same as a homework, and the quality of a final project. - Homework 1 (due Tues, Feb. 12)
- Homework 2 (due Tues, Feb. 28)
- Homework 3 (due Thurs, March 13)
- Homework 4 (due Tues, April 8)
Lectures
Dear readers from outside the class:
If you find these
lectures useful, please consider making a small donation (maybe $25 or
thereabouts, although any amount is appreciated)
to the Georgia Tech Foundation earmarked to go towards
my synthesizer research; the funds will go towards parts and equipment
for student projects.
Here
are instructions on how to donate.
- Session 1: 40 Years of Music Synthesis, Day 1 (Moog/Buchla up to DX7)
(video) - Session 2: 40 Years of Music Synthesis, Day 2 (DX7 and after)
(video) - Session 3: Op-Amp Review, Day 1
(video) - Session 4: Op-Amp Review, Day 2
(video) - Session 5: Meet the Korg MS-20, a typical semimodular analog monosynth
(video) - Session 6: Operation Transconductance Amplifiers (OTA), Voltage
Controlled Amplifiers (VCA)
(video) - Session 7: Voltage Controlled Oscillators (Sawtooth Cores)
(video) - Session 8: Exponential Current Sources
(video) - Session 9: Voltage Controlled Oscillators (Triangle Core)
(video) - Session 10: Circuits for Simple Waveshaping
(sorry no video available)- Related to circuits shown in class:
- 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,
IEEE International Solid-State Circuits Conference, Digest of Technical
Papers, Volume X, Feb. 1967, pp. 120-121.
- R. Williams,
- Other 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,
- Related to circuits shown in class:
- Session 11: Circuits for Complex Waveshaping
(Ken Stone’s wavefolder,
Buchla’s diodeless deadband circuit, Buchla’s timbre circuit)
(video) - Session 12: Aliasing Dangers in Digital Oscillators,
and Chebychev Waveshaping
(video)- T. Stilson and J. Smith,
Alias-Free Digital Synthesis of Classic Analog Waveforms,
International Computer Music Conference, 1996. - V. Valimaki,
Discrete-Time
Synthesis of the Sawtooth Waveform with Reduced Aliasing, IEEE Signal
Processing Letters, Vol. 12, No. 3, March 2005, pp. 214-217.
- T. Stilson and J. Smith,
- Session 13: Oscillator Sync and Frequency Modulation
(video)- E. Brandt,
Hard Sync
Without Aliasing
- E. Brandt,
- Session 14: OTA-C single-pole voltage controlled filters
(video)- Oberheim/Rossum patent,
Circuit for Dynamic Control of Phase Shift - ARP patent,
Frequency
Sensitive Circuit Employing Variable Transconductance
Circuit
- Oberheim/Rossum patent,
- Session 15: Four-pole VCFs, Day 1
(video)
N-Pole Filter Circuit Having Cascaded Filter Sections – careful,
the resonance feedback path drawn on the first page is in error! It should
be going to the negative terminal of the first OTA on the left.
- Session 16: Four-pole VCFs, Day 2
(video)- Moog patent,
Electronic High-Pass and Low-Pass Filters Employing the Bass to Emitter Diode Resistance of Bipolar Transistors - T. Stilson and J. O. Smith,
Analyzing
the Moog VCF with
Considerations for Digital Implementation,
Proceedings of the 1996
International Computer Music Conference, pp. 398-401. - A. Huovilainen,
Non-Linear
Digital Implementation of the Moog Ladder Filter, Proc. of the
7th Int. Conf. on Digital Audio Effects (DAFx’04), Naples, Italy, Oct. 5-8,
2004. - T.E. Stinchcombe,
Derivation of the Transfer Function of the Moog Ladder Filter, July 5, 2005
- Moog patent,
- Session 17: Four-pole VCFs, Day 3
(video) - Session 18: Four-pole VCFs, Day 4
(video) - Session 19: Properties of Second-Order Filters
(video) - Session 20: More Properties of Second-Order Filters, and
State Variable Filters
(video)- MIT 2.161 Signal Processing notes,
Op-Amp
Implementation of Analog Filters using the State-Variable Approach - Analog Devices
Interactive
Design Tools: OpAmps: Active Filter Synthesis - R. Johnson,
Programmable
State-Variable Filter Design For a
Feedback Systems Web-Based Laboratory - Daycounter, Inc. Engineering Services,
State
Variable Filter Design Equations
- MIT 2.161 Signal Processing notes,
- Session 21: Sallen-Key Filters
(video)- T.E. Stinchcombe,
A Study of the Korg MS10 & MS20 Filters, August 30, 2006
- T.E. Stinchcombe,
- Session 22: Odds and Ends
(video)
<!–
- 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 - 2/15 –
Analog Waveshaping, Part II: - 2/20 –
Single-pole OTA-based VCFs (and MOTM kit progress) - 3/1 –
Sallen-Key VCF theory; Buchla LPG example (Vactrol-based S-K) - 3/13 –
Sallen-Key
OTA-based examples; State-variable filter theory
(show & tell of assembled MOTM kits) - 3/15 –
State-variable VCF examples - 3/27 –
Transistor Ladder (Moog) and Diode Ladder VCFs, and a few other odds
and ends - 3/29 –
Exponential voltage-to-current conversion - 4/3 –
Sample playback and the dangers of aliased digital oscillators - 4/5 –
Alias-free synthesis of classic analog waveforms; digital state
variable filters (At some point, I say “I don’t know why you need a delay
here.” I have no idea why I said that… clearly you need a delay when you
code it up. I said some nonsense about stability – that’s not the issue.
Ignore anything I say that’s nonsense.) (First part of the lecture was devoted
to ads for some student activities, so you can skip ahead.) - 4/12 –
Digital emulation of a SSM2040/Prophet 5-style filter
(You can ignore anything after where I say “let’s try
matching the half-power point,” or something like that; I ran out of note
material and tried to freewheel it, and spun off into oblivion.
I was also just generally brain dead that day…) - 4/17 – Impulse invariance techniques
(alas, this appears to not have been taped…
sorry…) - 4/19 –
Demo of SSM2040/Prophet 5-style emulation VCF;
Waveshaping and Chebychev Polynomials - 4/24 –
Additive Synthesis - 4/26 – FM Synthesis–>
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. Here’s some
good ones:- 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 - V. Valimaki and A. Huovilainen,
Oscillator and Filter Algorithms for Virtual
Analog Synthesis, Computer Music Journal, Vol. 30, No. 2, 2006,
pp. 19-31. - T. Stilson,
Efficiently-Variable Non-Oversampled Algorithms in Virtual-Analog
Music Synthesis, PhD Thesis, Standford University, June 2006.
- Hal Chamberlin, Musical Applications of Microprocessors, 2nd