A keyboard used to play a number of separate synthesizers through MIDI messages.A master keyboard may be a conventional synthesizer, electronic piano, etc., but it may also be a controller keyboard with no sound generation circuitry of its own. Master keyboards are often used in complex studio setups in which all of the synths are connected to a sequencer; the synth to be played is selected using the sequencer's soft thru capability. This helps eliminate studio clutter and enables the use of rackmount synthesizers. Master keyboards that are meant to be worn with a strap over the shoulder, like a guitar, are sometimes used on stage.