Exam 1 - Midterm

MIDI

An acronym for Musical Instrument Digital Interface; a protocol that allows different MIDI devices to communicate using digital messages.

MIDI Timeline

Key events in the history of MIDI, including the proposal in 1981, public demonstration in 1983, and release of specs in 1983 and 2020.

Types of MIDI devices

MIDI Controller

MIDI Instruments

MIDI Sequencer

MIDI Controller

A device used to create and transmit MIDI messages, usually in the form of a keyboard.

MIDI Instrument

A device used to receive and playback MIDI messages, converting them into audio.

MIDI Sequencer

A multi-tracker recorder for MIDI hardware or software.

The MIDI cable

A MIDI  cable is used to connect one MIDI device to another It can also be used to connect MIDI devices to a computer through a MIDI interface

Daisy Chain

A configuration that connects multiple MIDI devices to a single controller using THRU ports.

Thru Box

a hardware device with one MIDI IN port and multiple THRU ports

Star Network

A Star Network is an alternate to Daisy Chaining with an advantage of all sound modules receiving MIDI messages at the same time

Merge Box

a hardware device that has multiple IN ports and one OUT port. The opposite of a THUR box!

Merging is a solution for a network with multiple MIDI controllers and one sharded sound module

MIDI channels

There are 16 MIDI channels (1-16) used to assign messages to specific instruments.

Most MIDI messages are assigned a MIDI channel ( the exception is the System Message)

100100000011110001000000

Due to four bits, there are 16 channels MIDI channels, 1-16

MIDI Modes

MIDI Modes determine how an instrument will respond to MIDI messages

Poly Mode: A MIDI instrument will respond to one MIDI channel

Omni mode: a MIDI instrument will respond to all MIDI messages

Signal Flow (MIDI Thru)

With an armed track. MIDI messages played by the controller will be transmitted to the instrument as long as it is selected in the track’s output and MIDI Thru is Checked in the Options menu

• Click

• MIDI Thru

MIDI Interface and adding a hardware instrument

A MIDI interface allows you to connect MIDI cables to a computer

The MIDI interface itself connects to the computer via USB

MIDI cables are used to connect hardware MIDI devices to the interface

Local control

Local Control is a switch on a keyboard synthesizer that disconnects the internal sound engine from the keyboard. Use it when sequencing with the synthesizer or you will get doubling

Audio MIDI Setup

What is the Audio MIDI Setup on Mac OS?

Found in the Utilities folder, it allows you to configure hardware MIDI and audio devices

Adding a hardware device in Audio MIDI Setup will allow it to show up in a MIDI track’s output

The MIDI Message Table

Message type (1 byte)	Message Date (1 or 2 bytes)
Note-On	Note Number 0-127 and Velocity Value 0-127
Note-Off	Note Number 0-127 and Velocity Value 0-127
Program Change	Program Number 0-127
Channel Pressure (Mono Aftertouch)	Pressure Amount 0-127
Polyphonic Key Pressure (poly Aftertouch)	Note Numbers 0-127 and Pressure Amount 0-127
Pitch Bend	Bend Amount with a 16,384 values
Control Change (CC)	CC number 0-127 and CC value 0-127
System Message	System message type 0-15*

*All messages can be assigned a MIDI channel (1-16) except for System Messages.

Note Number

There are 128 possible MIDI notes, ranging from 0 to 127. Every key (note) on a keyboard is assigned a number. For example, middle C- 60

Note number are assigned in Note-On, Note-Off and Polyphonic Key Pressure messages

Velocity Values

Velocity is the speed at which you strike your controller. A faster strike yields a higher velocity value

There are 128 possible velocity values, ranging from 0 to 127 with 127 being the highest (hardest)

Typically, this determines Loudness (dynamics) but it could be something else depending on the destination set in the instrument

A control must be velocity-sensitive to create note-on messages with different velocity values, otherwise all velocity values are 64

Velocity values are found in Note-on and Note-off messages

Program Change messages

There are 128 possible Program Numbers in a Program Change message ranging from 0- 127

Program changes are commonly used to change the program (preset) on a receiving MIDI instrument

Pitch Bend

A MIDI message used to bend the pitch of a note using a pitch bend wheel.

The wheel is bidirectional. At center, there is no pitch bend (0). Moving the wheel forward raises pitch, while moving it backward lowers pitch

Aftertouch (including types)

A MIDI message that modulates sound by applying pressure to keys after a note is played.

Aftertouch can be transmitted with MIDI as a continuous stream with values 0 to 127. Zero is no pressure amount and 127 is maximum pressure amount

Aftertouch types

o   There are two types of aftertouch messages

• Channel

• Polyphonic Key

CC (Control Change) Messages

MIDI messages that control specific parameters of an instrument, identified by a CC number and value.

 As shown in the MIDI Message Table, a CC MIDI message has a CC Number 0-127, and CC Value 0-127

Control Change

CC Number 0-127 and CC value 0-127

Control Change #1 Modulation

A message that controls modulation effects, typically associated with a mod wheel.

Most MIDI controllers have a Mod Wheel next to the Pitch Bend Wheel. It typically defaults to CC1 meaning CC1 messages will be generated and transmitted when moving it

The Mod wheel is unidirectional. All the way down, there is no modulation. Moving the wheel forward increases modulation from 0 to 127

Control Change #7 channel volume

 As the fader or knob is moved, a continuous stream of CC7 messages will be transmitted ranging from a value of 0 to 127, with 0 as silence and 127 maximum volume

  Control change #10 Pan

As mentioned previously, most MIDI controllers have faders and knobs. A good option for a knob is CC10, which is used to pan the MIDI instrument’s audio output

 

As the fader or knob is moved, a continuous stream of CC10 messages will be transmitted ranging from a value of 0 to 127, with 0 as hard left and 127 as hard right. Center is 64

 

      0                64                   127

Values =  - - - - - - - - - - - - - - - - - - - -

                  Left          Center          Right

  Control Change #64 Sustain Pedal

A sustain pedal connected to a MIDI controller is used to sustain a sound much like a traditional sustain pedal on a piano. The pedal is pressed to hold sound (after raising the hands) and released to stop (dampen) the sound

With MIDI, a value of 0-63 is off (pedal up) and a value of 64-127 is on (pedal down)

System Messages

MIDI messages that do not have channel assignments, used for system functions like synchronization.

All messages can be assigned a channel (1-16) except for

System Messages

System messages have no channel assignment

 

There are two system messages which is system Exclusive and Timing Clock there are more types of system messages

System Exclusive

System Exclusive can be used to copy stored presents from one MIDI device to another for the same type. For example, you can move presets from one Moog Voyager to another

You can also upload (backup) presets to a computer with an app like Sysex Librarian

Timing Clock

Timing Clock (also called Beat Clock) is used to sync tempo between a DAW and a hardware MIDI instrument (such as a drum machine)