A phaser is a type of guitar effect that creates a sweeping, whooshing sound by shifting the phase of an audio signal. It works by splitting the signal into two paths, then combining them again with a slight delay. The resulting effect modulates the frequencies of the sound, creating a series of notches and peaks in the frequency spectrum, giving it that distinctive “jet plane” or “spacey” sound.

Phasers are typically used for adding movement and depth to guitar or bass sounds, creating an ethereal or psychedelic vibe. They can range from subtle, sweeping sounds to intense, rhythmic pulses, making them a versatile addition to any effects chain. Many phasers have controls for rate, depth, and feedback, allowing players to adjust the intensity and speed of the effect.

Popular models like the Electro-Harmonix Electric Mistress, MXR Phase 90, and Boss PH-3 are renowned for their classic phaser sounds.