Theatre organ in the context of "Electric organ"

A pedalboard (also called a pedal keyboard, pedal clavier, or, with electronic instruments, a bass pedalboard) is a keyboard played with the feet that is usually used to produce the low-pitched bass line of a piece of music. A pedalboard has long, narrow lever-style keys laid out in the same semitone scalar pattern as a manual keyboard, with longer keys for C, D, E, F, G, A, and B, and shorter, raised keys for C♯, D♯, F♯, G♯ and A♯. Training in pedal technique is part of standard organ pedagogy in church music and art music.

Pedalboards are found at the base of the console of most pipe organs, pedal pianos, theatre organs, and electronic organs. Standalone pedalboards such as the 1970s-era Moog Taurus bass pedals are occasionally used in progressive rock and fusion music. In the 21st century, MIDI pedalboard controllers are used with synthesizers, electronic Hammond-style organs, and with digital pipe organs. Pedalboards are also used with pedal pianos and with some harpsichords, clavichords, and carillons (church bells).

The Leslie speaker is a combined amplifier and loudspeaker that projects the signal from an electric or electronic instrument and modifies the sound by rotating a baffle chamber ("drum") in front of the loudspeakers. A similar effect is provided by a rotating system of horns in front of the treble driver. It is most commonly associated with the Hammond organ, though it was later used for the electric guitar and other instruments. A typical Leslie speaker contains an amplifier, a treble horn and a bass speaker—though specific components depend upon the model. A musician controls the Leslie speaker by either an external switch or pedal that alternates between a low and high speed setting, known as "chorale" and "tremolo".

The speaker is named after its inventor, Donald Leslie, who began working in the late 1930s to get a speaker for a Hammond organ that better emulated a pipe or theatre organ, and discovered that baffles rotating along the axis of the speaker cone gave the best sound effect. Hammond was not interested in marketing or selling the speakers, so Leslie sold them himself as an add-on, targeting other organs as well as Hammond. Leslie made the first speaker in 1941. The sound of the organ being played through his speaker received national radio exposure across the US, and it became a commercial and critical success. It soon became an essential tool for most jazz organists. In 1965, Leslie sold his business to CBS who, in 1980, sold it to Hammond. Suzuki Musical Instrument Corporation subsequently acquired the Hammond and Leslie brands.