Home Recording Basics: Managing MIDI Modes
Your synthesizer, drum machine, or other MIDI module has the following four operating modes that dictate how your instrument responds to the MIDI messages it receives:
Mode 1 — Omni On/Poly: In Omni On/Poly mode, your instrument responds to all the MIDI messages coming across the wires (well, except the MIDI channel data). This means that your synthesizer or other device tries to play the parts of all the instruments hooked up to your MIDI controller. In this mode, your device also plays polyphonically (more than one note at a time).
Some older MIDI devices default to Omni On/Poly Mode (Mode 1) when you turn them on. In this case, you need to reset your instrument if it’s one of several in your MIDI setup. If you don’t, the instrument responds to any MIDI messages sent from the controller, not just the ones directed toward that instrument.
Mode 2 — Omni On/Mono: Omni On/Mono mode allows your device to receive messages from all MIDI channels but only lets it play one note at time (monophonically). This mode is rarely, if ever, used.
Mode 3 — Omni Off/Poly: In the Omni Off/Poly mode, your device can play polyphonically but responds only to MIDI signals on the channels that it’s set to. This is the mode you use most often when sequencing.
Mode 4 — Omni Off/Mono: In the Omni Off/Mono mode, your instrument responds only to the messages sent on the MIDI channel that it’s set to and ignores the rest. Rather than play polyphonically, as in mode 3, your instrument plays only one note at a time. This can be advantageous if you’re playing a MIDI controller from an instrument that can play only one note at a time, such as a saxophone.