Introduction to MIDI
Introduction to MIDI:
MIDI is a
serial communication protocol from the 80s which is very widespread in music but also other control applications (e.g. stage lighting). It is based on a byte-messages format which results in command messages usually combined of an index number for type of command (e.g. control change, note on) and a message that specifies the command properties.
For instance, a MIDI message may be: Note On, Note Number 76, Note Velocity 93.
The
range of the values usually is 0-127 (128 discreet values - only 7 bits are used). For parameters like Pitch Bend, two message bytes are combined to achieve a resolution of 16384 steps, divided into 8192 and -8192.
The
types of MIDI messages that are relevant for our purpose are:
- Note ON
- Note OFF
- Control Change (for realtime change of parameters of sound generators or effects)
The advantage of MIDI is: reliabilty, widespread industry standard, virtually every sound device/software "speaks" it. The standard is conventionalized and works "out of the box".
The disadvantes is: slow speed, limited transfer media, not as flexible as e.g. OSC.
Setting Up MIDI
You need: a control keyboard, the software Midi Monitor (MAC) or MIDI OX (Windows), if necessary: a driver for the Keyboard
First, connect the MIDI Controller (e.g. Keyboard) and make sure messages arrive at the computer (check with MIDI Monitor / MIDI OX application after selecting the correct input interface). If not check that the USB port has enough power and that the driver is installed.
Check that all Sliders / Knobs output "Control change" type messages. If some output something else, or output multiple datastreams, then you have to use the hardware interface or a software editor to change this: MIDI control keyboards usually come with a software to edit what the keys and the sliders do (the messages they transmit). If necessary, install MIDI mapping editor for keyboard (in the case of the EDIROL PCR-30 this is the e
PCR-Editor!
- NOTE: some host SW has fixed mappings of certain control changes (eg garageband). Mulab doesn't do this, and allows you to freely map control changes!
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