The term 'Pedal Effect on a Guitar' refers to the use of an electronic device, such as a pedal, to alter the sound of a guitar. The most common type of pedal effect is an ECHO, which produces a reverberating sound that can be used to create a variety of musical effects. ECHO pedals are often used in rock and metal music to create a more powerful sound. They can also be used to create a more ambient sound, or to add texture to a guitar solo.