Since its inception nearly 60 years ago, the commercial synthesizer has reinvented itself in numerous ways that seek to widen the palette of tones, timbres and effects that this versatile and ubiquitous instrument has to offer. Here’s a list of the most common synthesis types.
This is the oldest and most popular type of synthesis. It’s also one of the most recognizable for its peculiar retro sound so reminiscent of the early days of synthesis and electronic music. The basic workflow of subtractive synthesis begins with a small set of sound generators called oscillators that produce looped patterns of simple waveforms with a small set of shapes such as sine, triangle, square, sawtooth, pulse and noise that can be stacked and mixed in order to obtain a more complex and rich starting sound. This raw signal is then shaped and processed through various modules such as filters, low frequency oscillators and envelopes that create a more polished and refined tone through the subtraction of unwanted frequencies and harmonics. Useful for projects in need of electronic retro sounds as well as a very synthetic touch.
The mathematical principles of additive synthesis were laid out way before the rise of commercial synthesizers by Joseph Fourier at the beginning of the 19th century.
The basic principle of additive synthesis is that of creating complex waveforms through the addition of simple ones such as sine waves. This synthesis method revolves around the idea of a central tone called fundamental to which a series of harmonics or partials is added, which results in more complex waveforms and harsher, more metallic tones. Good for very clean and pure digital tones.
FM synthesis was first introduced commercially by Yamaha in 1980 with the Yamaha GS-1.
FM synthesis is very similar to additive synthesis in its use of harmonics as a way to achieve more complex and sophisticated waveforms that can go from very simple and pure sine based tones to extremely intricate waveforms saturated of harmonic content. These changes in the harmonic structure of a waveform in FM synthesis are achieved through the modulation of the frequency of the main oscillator, also called the carrier, by another oscillator called the modulator.
Wavetable synthesis was developed by Wolfgang Palm of Palm Products GmbH (PPG) in the late 1970s and published in 1979, and has since been used as the primary synthesis method in synthesizers built by PPG and Waldorf Music. This synthesis method introduces a very powerful innovation consisting on the ability to transition between sets of waveforms or tables, which allows us to morph the tone and the harmonic structure of the sound in real time with nothing more than the oscillators, giving us access to a much wider range of sounds within each patch, as well as a more expressive and dynamic control of the sound. Capable of reproducing extremely synthetic sounds as well as decent recreations of acoustic and organic elements.
The origins of sampling can be found in a style of contemporary music called Concrete Music formulated by Pierre Schaeffer, and then further developed by composers like John Cage, Edgar Varèse, Karlheinz Stockhausen and Iannis Xenakis. Sampling is by far the most realistic type of synthesis when it comes to acoustic instruments emulation as well as the reproduction of organic sounds and field recordings. Instead of relying on looped waveforms to produce sound, samplers use entire sound recordings stored in memory that can be mapped to the keyboard and then triggered in real time.
The first commercially available physical modelling synthesizer made using waveguide synthesis was the Yamaha VL1 in 1994. This synthesis type is based on the recreation of complex sonic structures through the analysis and creation of mathematical equations and algorithms that describe the sounds produced by the interactions that occur between physical bodies. These mathematical formulas are able to produce very complex waveforms straight away, without the need to do any additional work on their harmonic structure, and even provide various parameters to control key variables of their formulas in order to create some real time variation. Great for acoustic recreations with a twist.
Greek composer Iannis Xenakis is known as the inventor of the granular synthesis technique, while Canadian composer Barry Truax was one of the first to implement real-time versions of this synthesis technique. Granular synthesis is based on the deconstruction of waveforms into smaller slices called grains that can then be rearranged according to different algorithms in order to produce entirely new complex waveforms. The grains can also be manipulated through various parameters such as length, amount and pitch variation in order to create morphing and evolving sounds. Good for experimentation and sound design.
These are the most common types of synthesis available to the modern composer. Each has its strengths and weaknesses, so there’s not a single type capable of handling all the possible genres, moods and styles; therefore It’s important to get familiar with all of them in order to discern which is best for each application.