An electric guitar effect is a device or technique used to modify the sound of an electric guitar. The three most common effects are phaser, REVERB, and wawa. A phaser is an effect that creates a sweeping sound by combining two signals out of phase with each other. REVERB is an effect that simulates the sound of an acoustic space, such as a concert hall or a cave. Wawa is an effect that creates a pulsing sound by modulating the volume of the signal.