A rotary effect simulates the sound of a rotating speaker, like the classic Leslie speaker, often used in organ amplification. It creates a swirling, moving sound by altering the pitch and volume of the signal in a way that mimics the rotation of the speaker’s horn. The rotary effect typically involves a combination of modulation and speed controls, letting you adjust the rate of the rotation and the intensity of the sound.

Rotary pedals can be used to add a dynamic, vibrant character to your tone, especially in genres like blues, rock, and jazz, where it’s used to create a lush, atmospheric effect. The sound often has a 3D, pulsating feel, making it ideal for creating a sense of movement and space within the music.