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.
Concepts in programming The MC-4 can be programmed with the input of number values, using the control panel numeric keypad. When programming a sequence of notes into the MC-4 numerical values are entered. These correspond to the musical notes on a
piano keyboard;
Middle C would have the value of 24, increasing upwards for higher notes and downwards for lower notes. Alternatively, the MC-4 can record live playing from a monophonic keyboard.
Syncing to MIDI The MC-4 can be synched to
MIDI using a clock to
DIN converter. When the MC-4 is powered up, the display will show the TB (time base) default of 120. This is the number of clock pulses per bar; this was the standard before DIN and
MIDI clock came into being. If a sequence is programmed while the MC-4 is set to the default TB, it will never sync correctly to DIN or
MIDI clock. To sync correctly, the MC-4 TB needs to be set as 48/12/6, this sets the MC-4 for
DIN sync and defaults the step time to 16ths (12 clocks) and the gate length to 32nds (6 clocks).
Cassette Storage After a sequence has been programmed it must be saved, as the memory is volatile: when the power is switched off, memory contents are lost. An optional digital cassette recorder, the
Roland MTR-100 was available for this purpose. The owners manual shows that a programmed sequence could also be saved to a standard
cassette deck. This is good news as the MTR-100 is quite rare to find. When saving or loading programs, the CMT (Cassette Memory Transfer) mode must be selected. Programs are saved using program numbers for identification. ==Computer-based sequencer programming==