Phase distortion synthesis is a sound synthesis technique that alters the phase of a waveform to create new timbres. Unlike traditional methods that modify amplitude or frequency, this approach focuses on changing the phase relationships between different harmonics of a sound. This can lead to unique and complex sounds that are not easily achievable with other synthesis methods. This technique was popularized by the Yamaha DX7 synthesizer in the 1980s, which used it to generate a wide range of sounds, from realistic instruments to abstract textures. Phase distortion synthesis allows for greater flexibility in sound design, making it a valuable tool for musicians and producers.