Sound Design Theory: 8 Types of Audio Synthesis
Education
Introduction
In the previous episode, we explored the concept of layering in sound design and how it can be achieved by stacking oscillators. However, even without layering, there is a vast range of possibilities for creating unique sounds using just two oscillators. In this article, we will delve deeper into sound synthesis and explore eight different types of audio synthesis techniques.
Additive Synthesis
Additive synthesis involves creating sound by adding harmonics to the sound. This can be achieved by stacking oscillators on top of each other and using sine waves to add harmonics one by one. The waveform of the sound changes with each harmonic added, allowing for flexible shaping of the sound. Additive synthesis can be done in synths like Ableton's Operator or Serum, where each vertical bar represents a harmonic in the harmonic series.
Subtractive Synthesis
Subtractive synthesis, on the other hand, starts with a sound rich in harmonics and then removes some of them using filters. Filters like low pass and high pass can be used to cut specific frequencies, resulting in a less harsh or more muffled sound. Subtractive synthesis works well when combined with a sound that already has a lot of harmonics.
Wavetable Synthesis
Wavetable synthesis uses a collection of waveforms, known as tables, to create sounds. These tables can be morphed or interpolated between to add motion and variety to the sound. Some synthesizers, like Serum, allow you to import your own waveforms or draw your own, expanding the possibilities even further.
Amplitude Modulation (AM) Synthesis
AM synthesis involves using one oscillator (the modulator) to control the volume of another oscillator (the carrier). As the modulator oscillates, it changes the amplitude or volume of the carrier, adding harmonic content to the original signal. Different waveforms can be used for both the carrier and the modulator, resulting in a wide range of tonal possibilities.
Ring Modulation
Ring modulation is a variation of amplitude modulation where only the added harmonics remain and the original frequency of the carrier disappears. This creates a metallic or bell-like effect and can be a unique way to shape sounds.
Frequency Modulation (FM) Synthesis
FM synthesis is similar to AM synthesis, but here the modulator controls the frequency or pitch of the carrier oscillator. As the modulator oscillates, it distorts the carrier waveform and adds a rich harmonic content. FM synthesis is known for its versatility and was popularized by synths like the DX7.
Wave Shaping Synthesis
Wave shaping synthesis starts with a simple waveform and distorts it using a wave shaper. This type of synthesis allows for various forms of distortion, such as saturation, wave folding, and phase inversion. It can add unique character and texture to sounds.
Hard Sync Synthesis
Hard sync synthesis involves two oscillators, with one oscillator resetting the cycle of the other at each wave cycle. This creates a break in the waveform and introduces a distinctive distortion effect. The pitch and timbre of the resulting sound can be controlled by the frequencies of the two oscillators.
Granular Synthesis
Granular synthesis uses audio samples as the sound source, slicing them into tiny grains and manipulating them in various ways. Each grain can be layered, played at different speeds and lengths, and adjusted in volume. Granular synthesis is often used to create ambient or textured sounds.
These eight types of audio synthesis offer a wide array of possibilities for sound designers and musicians alike. By understanding the principles behind each technique, you can explore new sonic territories and create unique sounds that will elevate your music production.
Keywords
Additive synthesis, subtractive synthesis, wavetable synthesis, AM synthesis, ring modulation, FM synthesis, wave shaping synthesis, hard sync synthesis, granular synthesis
FAQ
What is the difference between additive and subtractive synthesis? Additive synthesis involves adding harmonics to a sound by stacking oscillators, while subtractive synthesis removes certain harmonics using filters.
How does FM synthesis work? FM synthesis uses a modulator oscillator to control the frequency or pitch of a carrier oscillator, resulting in rich harmonic content and unique tonal possibilities.
Can I create my own waveforms in synthesis? Yes, some synthesizers allow you to draw your own waveforms or import audio samples to use as waveforms.
What is the benefit of granular synthesis? Granular synthesis allows for the manipulation of audio samples in tiny grains, offering flexibility in creating ambient and textured sounds.
How can I shape the sound in FM synthesis? By adjusting the amplitude and frequency of the modulator oscillator, you can control the harmonic content and overall character of the FM-synthesized sound.