Editing Musical keyboard (section)

==Keyboards with alternative sets of keys==
There are some rare variations of keyboards with more or fewer than 12 keys per octave, mostly used in [[microtonal music]], after the discoveries and theoretical developments of musician and inventor [[Julián Carrillo]] (1875–1965).

Some free-reed instrument keyboards such as [[accordion]]s and Indian [[Pump organ|harmonium]]s include microtones. Electronic music pioneer [[Pauline Oliveros]] played one of these. Egyptian belly-dance musicians like [[Hossam Ramzy]] use custom-tuned accordions so they can play traditional scales. The small [[Garmon]] accordion played in the [[music of Azerbaijan]] sometimes has keys that can play microtones when a "shift" key is pressed.