Probably the most simple expression pedal
made for use with a guitar
or other electric instrument. A potentiometer
with variable resistance
controlled by a large foot pedal.
On "full" (least resistance), this pedal allows the signal from the pickups to reach the amplifier without attenuation. Depressing the pedal toward the heel progressively diminshes the signal strength reaching the amp and, therefore, reduces the volume of the instrument.
This pedal is essentially redundant to the volume knob on the electric guitar (or other instrument) being played. However, it is a popular tool; twiddling the volume knob on your guitar is difficult to do while strumming or picking.
Allows creative use of dynamics, including volume swells and signal cuts.
Visually similar to a wah wah pedal, though most look like the Ernie Ball 6166 (the "industry standard"), which is undecorated steel with a black rubber traction pad for the player's foot. Most wah wah pedals attempt to visually emulate the CryBaby model, which is entirely black.