The phaser pedal offers yet another great modulation effect that any discerning guitarist will make great use of. The sweeping phase effect has been popular for decades and many musicians have taken advantage of it, sometimes to simply add some extra body and depth to their work, and sometimes to completely identify their work by it.
The spiralling, trance-inducing sweeping effect of the phaser pedal is created using the same fundamental principles as its flanger or chorus cousins. Your guitar signal is split into two and one of them is processed by an all-pass filter creates a spiralling/warped sound; an effect that is achieved when your signal is split into two and one is sent through an all-pass filter, then through an LFO, before being reunited with the dry signal.
The resulting blend has a sweeping, soft, hypnotic sound that has been utilised to great effect by artists and bands such as Thin Lizzy, The Smashing Pumpkins and Van Halen.
Phaser pedals allow you to set the rate and depth of the modulation effect to your required tempo and control the “direction” of your phase effect within its sonic environment.