Phasor (sound synthesizer)

Apple II Phasor - Plastic Forks

Phasor is a term used in the context of sound synthesis, particularly in electronic music, to describe a type of synthesizer or synthesis technique that employs phase modulation or phase distortion to generate complex audio signals. Phasor synthesis is closely related to, and often confused with, Frequency Modulation (FM) synthesis and Phase Distortion Synthesis, both of which manipulate the phase of a waveform to create new sounds. However, phasor synthesis specifically refers to the manipulation of the phase of a signal to produce timbral variations and harmonic complexity.

Overview

Phasor synthesis operates by modulating the phase of a waveform, typically a sine wave, with another waveform. This modulation affects the timing of the waveform's cycle, creating shifts and changes in the harmonic content of the resulting sound. Unlike FM synthesis, which modulates the frequency of the carrier wave, phasor synthesis directly manipulates the phase, leading to different sonic characteristics and textures.

Applications

Phasor synthesis is utilized in various synthesizers and software to create evolving pads, atmospheric textures, and other complex sounds that are rich in harmonics. It is particularly valued in ambient and experimental electronic music, where its capacity for creating unique and evolving sounds is highly prized.

Technical Aspects

The basic principle behind phasor synthesis involves the use of a phasor—a unit vector in the complex plane that rotates with a frequency corresponding to the signal's phase. By modulating this phasor's rotation, the phase of the audio signal is altered, which in turn affects the waveform's shape and harmonic content. This process can introduce a wide range of harmonic and inharmonic content into the sound, depending on the modulating signal's frequency, amplitude, and waveform shape.

Comparison with Other Synthesis Techniques

While phasor synthesis shares similarities with FM and phase distortion synthesis, it is distinct in its approach to sound generation. FM synthesis focuses on frequency modulation to create complex sounds, whereas phase distortion synthesis alters the shape of a waveform through non-linear phase modulation. Phasor synthesis, by directly manipulating the phase, offers a different set of possibilities for sound design, providing a unique tool for synthesists and composers.

Implementations

Several synthesizers and software instruments implement phasor synthesis or related techniques, allowing users to explore its potential for sound design. These tools often provide intuitive interfaces for manipulating phase relationships, enabling the creation of dynamic and evolving sounds.

Conclusion

Phasor synthesis represents a unique and powerful approach to sound generation in electronic music. By focusing on the manipulation of phase, it offers sound designers and musicians a distinct set of tools for creating complex and evolving sounds. As technology and software continue to evolve, the potential applications and developments in phasor synthesis are likely to expand, further enriching the palette of sounds available to electronic musicians.