Sound Module

A Sound module (sometimes referred to as tone generator) is an electronic musical instrument without a human-playable interface such as a keyboard, for example. Sound modules have to be "played" using an externally connected device. The external device may be a controller, which is a device that provides the human-playable interface and may or may not produce sounds of its own, or a sequencer, which is computer hardware or software designed to play electronic musical instruments. Connections between sound modules, controllers, and sequencers are generally made with MIDI, which is a standardized protocol designed for this purpose.
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