What is a Phaser?

A phaser is an audio effect that creates a sweeping, swirling sound by shifting the phase of an audio signal and blending it with the original signal. The effect works by splitting the signal into two paths, altering the phase of one path, and then recombining them. When the two signals interact, certain frequencies are reinforced while others cancel out, creating a moving and textured sound.

Phaser effects typically use a low-frequency oscillator (LFO) to continuously change the phase shift over time. As the phase relationship between the signals changes, a series of peaks and dips move across the frequency spectrum. This produces the characteristic sweeping sound that is often described as smooth, watery, or swirling.

Phasers are commonly used in music production on guitars, keyboards, synthesizers, and sometimes vocals. The effect became especially popular in rock and funk music during the 1970s and later appeared in electronic and modern pop production. By adjusting parameters such as rate, depth, and feedback, producers can create subtle movement or dramatic phase-shifting effects.