The Roland MC-4 MicroComposer was an early microprocessor-based music sequencer released by the Roland Corporation. It could be programmed using the ten key numeric keyboard or a synthesizer keyboard using the keyboards control voltage and gate outputs. It was released in 1981 with a list price of US$3,295 (¥430,000 JPY) and was the successor to the MC-8, which in 1977 was the first microprocessor-based digital sequencer.
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