OM# Documentation

Sending MIDI

There exist different means to send MIDI messages out from OM#. The main situations are:

• Playing a Score or MIDI object: CHORD, CHORD-SEQ, VOICE, POLY, MIDIEVENT, MIDI-TRACK…
• Sending out through the functions of the “MIDI/Out” package: these functions send MIDI when evaluated (→).
• Assigning an action to other playable structures like BPF (see Continuous Controllers).

All MIDI-out events are sent to a specified port (or to the default MIDI out port if unspecified). See MIDI Settings for details about how to configure and connect MIDI ports to synthesizers.

Note — Microintervals: Setting the pitch bend of some MIDI channels (in particular, using the pitchwheel function) is a means to let MIDI synthesizers render microintervals when playing OM# score objects. See the different options for microtonal tuning in the Preferences / Score tab.

MIDI / General MIDI Standards

MIDI events can be of different types, and the semantics of values is generally unified through a number of layers of the standard protocol (most notably, the “General MIDI” standard).

OM# provides a set of utilities to get these to numeric values required to initialize MIDI events or MIDI sending functions, using input menus:

• midi-type: allows to select a MIDI event type identifier

• midi-control-change: retuns the number corresponding to a given controller (e.g. “Volume”, “Pan”, “PitchBend”, …) suitable to parameterize the first value of a ControlChange event.

• gm-program: returns the program number corresponding to a given instrument timbre, suitable to set the second value of a MIDI event of type “ProgramChange”.

• gm-drumnote: returns the pitch (or key number) corresponding to a given drum, suitable to set the first value of a KeyOn/KeyOff event sent on channel 10.
• mc-to-pitchwheel: returns the value corresponding to a given number of midicents pitch shifting, suitable to set the second value of a “PitchWheel” ControlChange event.