Phaser

Electronic filter
A phaser pedal is a type of electronic filter. The effect consists of a filter and a mixer. The effect splits the input signal into two identical parts. The first part remains unprocessed and the second part goes through a filter where different frequencies are filtered. Often the different peaks and valleys of the filter are controlled by an LFO, a low frequency oscillator. If you then mix both signals in the same ratio, the well-known phasing effect is created.

The phaser, when modulated by a low-frequency oscillator, is closely related to the flanger. The difference is that a phaser often has an irregularly shaped frequency response. The flanger always has peaks and valleys equidistant from each other.

The two most famous guitar phaser pedals are the MXR Phase 90 and the Electro Harmonix Small Stone. Phasers aren’t just used as an electric guitar effect. You also encounter the effect in electronic music production. In addition, you often hear it with the Beatles and other music from the 60s and 70s.