1. Types of Synthesizers and How They Work
By: Steven Baker

2. Outline What is a synthesizer? History of synthesizers
Waveforms and Harmonics
Components of synthesizers
Different types of synthesis

3. What is a Synthesizer? Creates vibrations like any instrument
Modular
Creates vibrations like any instrument
Vibrations in the form of an electrical signal
Signal able to be modified and manipulated in ways that are not possible with acoustic instruments
Modular vs. All-In-One
All-In-One

4. History of Synthesizers
RCA Mark II
History of Synthesizers
RCA Mark II Sound Synthesizer (1957)
First programmable sound synthesizer
Moog Synthesizer (1964)
First commercially available modern synthesizer
Much more compact due to development of integrated circuits
Yamaha GS-1 (1981)
First digital FM (frequency modulation) synthesizer
Software Synthesizers (1990’s – today)
Moog Synthesizer
Massive (softsynth)

5. Analog vs. Digital
Analog synthesizers use analog circuitry to generate a signal
Digital synthesizers use digital signal processing (DSP) to generate a signal
Digital synths typically offer more features at a given price
Certain types of synthesis are only feasible with digital

6. Waveforms
Synthesizers use alternating current to create their electrical signal
The way this current changes overtime can be represented as a waveform
The shape of the waveform determines what the signal actually sounds like (timbre)
Shapes of waveforms can be simple, complex, or even completely random

7. Examples of Waveforms Sine Wave (440Hz) Sawtooth Wave (440Hz)
Triangle Wave (440Hz)
Amplitude
Frequency (440Hz and 880Hz)

8. Harmonics
Sine Wave (100Hz)
The reason sound waves sound different is because they have different harmonic content
Harmonic
Multiple of a fundamental (original) frequency
Example: 100Hz note
2nd harmonic = 200Hz
3rd harmonic = 300Hz
Etc.
Sawtooth Wave (100Hz)
Triangle Wave (100Hz)

9. Components of a Synthesizer
Hardware components for a basic analog synthesizer
Voltage-controlled Oscillator
Generates original waveform that is then manipulated by other components
Voltage-controlled Filter
Help shape a sound by filtering out unwanted frequencies
Essential to subtractive synthesis
Voltage-controlled Amplifier
Boosts the electronic signal before it is sent to be played from a speaker
Envelope Generators
Help shape the sound further

10. Subtractive Synthesis
Triangle Wave (100Hz) Before Low-Pass Filter
Primarily used by older, analog synthesizers
Start with waveform then subtract away until desired sound is achieved
Use of filters to subtract away
High-Pass
Low-Pass
Band-Pass
Band-Reject (Notch)
Cutoff Frequency
Triangle Wave (100Hz) After Low-Pass Filter

11. Additive Synthesis
Based on the idea that any sound can be made by combining a series of sine waves at various frequencies
Typically digital
Not feasible with analog
Most sounds in nature are complex
100’s if not 1000’s of sine waves to be accurately reproduced
Not limited to just sine waves
Any types of waves can be mixed to create new, interesting sounds
Three sine waves
(100Hz 300Hz and 500Hz)

12. FM Synthesis Frequency Modulation Two Waves
Sine wave (440Hz)
Frequency Modulation
Two Waves
Carrier (actually heard)
Modulator (controls pitch of carrier)
Usually only implemented in digital synthesizers
Example: Yamaha GS-1
880Hz
220Hz
Result of carrier modulated over time

13. Conclusion What a synthesizer is History of synthesizers
Waveforms and Harmonics
Components of synthesizers
Different methods of synthesis

14. References http://synthesizeracademy.com