Roland MC-4 Microcomposer

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. Like its predecessor, the MC-4 is a polyphonic CV/Gate sequencer.

This sequencer was released before the advent of MIDI, and viewed by some composers to have more accurate timing. The MC-4 has an output patchbay to the right of the control panel, allowing you to patch the MC-4 to a synthesizer using 3.5mm patch cords. There are four channels of outputs containing CV-1, CV-2, Gate and MPX (multiplex) to control four separate synthesizers. To the left of the output patchbay there are two switches and a control knob. The control knob alters the tempo of the sequencer. The first switch is for cycle mode (which allows the programmed sequence to repeat continuously until the sequencer is stopped), the second switch is for sync control. The MC-4 can be synced to other Roland equipment such as a drum machine or another MC-4 MicroComposer (offering eight separate channels of sequencing).

In the centre of the control panel is the numeric keypad and enter button. To the right of this are two blue keys for moving forward or backwards through a programmed sequence. Below the two advance keys there is another blue button used to tell the MC-4 that you have finished programming a single measure, for example a one bar phrase of notes. To the left of the numeric keypad are six more buttons. These buttons are used for editing the sequence that has been programmed; they include insert, delete, copy-transpose and repeat. The bottom two buttons are for moving the cursor on the screen from left to right.

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