Exam 1 - Midterm

An Introduction to MIDI

1. What is MIDI?

an acronym for Musical Instrument Digital Interface

MIDI is not AUDIO it is a protocol that allows different MIDI devices to communicate with each other using digital messages

When connecting an interment controller to an MIDI instrument using a MIDI cable the messages is transmitted to the MIDI instrument which will convert to AUDIO

2. MIDI Timeline

·     October of 1981

o  Dave Smith of Sequential Circuits proposed the Universal Synthesizer Interface as an interconnection for synthesizers. Over the following year, the name was changed to Musical Instrument Digital Interface (MIDI)

·     January of 1983

o  MIDI was demonstrated to the public for the firsr time at the NAMM Show when Roland JP-6 and Sequential Circuits Prophet 600 were connected with MIDI cables

·     August 1983

o  The MIDI spec 1.0 was published

·     January 2020

o  The MIDI spec 2.0 was introduced at the NAMM Show

3. Types of MIDI devices

MIDI Controller

MIDI Instruments

MIDI Sequencer

4. MIDI Controller

is used to create and transmit MIDI messages by playing it

It is primarily used to create and transmit MIDI messages (your performance)

A MIDI controller is usually a keyboard but there are others types, such as a woodwind controller

Allows skilled performers to instantly create MIDI messages by applying their skills

It does not have an internal sound engine and therefore, does not typically receive MIDI signals or produce an audio output signal

5. MIDI Instruments

·     is primarily used to receive and playback MIDI messages (convers MIDI to audio) Hardware or software

o  A sound module is a keyboard synth sound engine without the keys

o  The Yamaha TX-7 sound module was a Yamaha DX-7 synthesizer without the keyboard

o  Sound modules take up less space

o  A MIDI instrument can also be software on a computer. In this case, it is referred to as a virtual instrument and can be used stand-alone or as a plug-in within a DAW (AAX, VST, AU)

o  There are many types: synthesizers, samples, drum instrument, etc.

o  Drums

ProTools BOOM is a simple plugin

ProTools GROOVECELL is another drum machine

EZDRUMMER a software that is for acoustic drum kit that sounds like a real drum kit

BATTERY a native instruments it’s more for electronic kit

Spectrasonics STYLUS RMX is good for loop

o  Bass

Spectrasonics TRILIAN is good for acustic bass, electric basses, synth base

o  Keys

ProTools MINI GRAND is a decent sounding acoustic

ProTools DB-33 is a decent sounding organ

Spectrasonics KEYSCAPE is a fantastic sounding plugin it has a piano, electronic piano, etc.

o  Synthesizers

ProTools SYNTHCELL

ARP 2600

 Arturia MINI V

 Xfer Records SERUM

Arturia PIGMENT

6. MIDI Sequencer

·     is a multi-tracker recorder for MIDI hardware or software

o  MIDI Sequencers appeared shortly after the birth of MIDI and were utilized in various ways including stand-alone hardware sequencers, software applications on a computer and keyboard workstations

o  Today, MIDI Sequencers are a part of any DAW including Pro Tools, Ableton Live and Logic Pro

o  A MIDI or instrument track is used to record, edit, and playback MIDI data in a piano roll. It can be compared to a scroll used for a player piano

MIDI Connections Hardware

1. The MIDI cable

o   A MIDI  cable is used to connect one MIDI device to another

o   It can also be used to connect MIDI devices to a computer through a MIDI interface

o   Each end has a 5-pin DIN connecter

• In reality, only pins 2, 4 and 5 are used

o   Transmission rate is slow 31.25Kbaud, or 31,250 bits per second

o   MIDI cables are uni-directional

o   MIDI messages travel one bit at a time. This is called serial transmission. 1→0→0→ 1

o   In general, it is suggested to use a MIDI cable shorter than 50 feet (Use Ethernet MIDI for long distances).

3. All connection configurations: simple, daisy-chain, etc.

·       Daisy Chain

o   A Daisy Chain network is a solution when multiple instruments need to respond to a single controller

o   A basic connection is used for Sound Module 1 but the THRU port will be used to forward MIDI to sound Module 2

o   This can be expanded by adding more sound modules and continuing to go THUR to IN for each module

·       THRU BOX

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

·       Star Network

o   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

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

·       Merging

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

4. MIDI channels

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

• 100100000011110001000000

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

o   The MIDI channel is assigned to messages by the TX channel setting on a controller

o   A MIDI instrument’s RX channel setting will determine which MIDI messages it will respond to

5. MIDI Modes

o   MIDI Modes determine how an instrument will respond to MIDI messages

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

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

o   Module 2 will ignore incoming MIDI messages but module 1 will still respond

MIDI Connections Computer

1. Signal Flow (MIDI Thru)

o   MIDI messages are created by playing keys and pads, or moving wheels, knobs, sliders and pedals on the MIDI Controller

o   MIDI messages are transmitted to your computer and received by an app such as Pro Tools. A track must be armed to receive them

o   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

o   MIDI messages are converted to audio signals and monitored by an audio interface

2. MIDI Interface and adding a hardware instrument

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

o   The MIDI interface itself connects to the computer via USB

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

o   A MIDI interface can have multiple pairs of MIDI IN/OUT ports (the MOTU MIDI Micro Lite has four pairs on the back and one pair on the front

3. Local control

o   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

4. Audio MIDI Setup

o   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

MIDI Messages Parts 1 and 2

1. The MIDI Message Table

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

2. Note Number

o  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

o  An 88-note keyboard goes from note numbers 12 to 108 (without transposition)

o  Numbers can also be represented as letters. For example, middle C= C3

o  The total range is C-2 to G8 and an 88-note keyboard goes from A-1 to C7

o  Numbers and letters are found in MIDI editors

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

3. Velocity Values

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

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

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

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

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

4. Program Change messages

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

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

o  Changing a program number on this controller will cause the receiving MIDI instrument to change to the same program number

5. Pitch Bend

o  Most MIDI controllers use a wheel for bending the pitch of a sounding note. Hence, it is called the pitch bend wheel

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

o  The Pitch Bend Range is the musical interval reached at maximum and minimum

o  Like in our previous example, moving the pitch bend wheel on a controller will send pitch bend messages resulting in the same pitch change from a receiving MIDI instrument

6. Aftertouch (including types)

o   With an aftertouch-capable keyboard controller, you can modulate (change) a sound by applying pressure to keys

o   For example, while holding a note on your controller, vibrato can be applied by pressing harder (adding pressure) on the key. As more pressure is added, more depth (amount) is applied to the vibrato

o   Aftertouch can make other changes to sound such as timbre or loudness

o   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

o   With channel pressure, the same amount  of pressure will be applied to every note

o   With Polyphonic Key pressure, a different amount of pressure can be applied to each held note

o   In the diagram, two notes are being held but with pressure being added to just one note

• With Channel pressure, both notes will modulate at the same amount

• With Polyphonic pressure, just one note, the one being held, will modulate

7. Control Change

o   The Control Change message (CC for short) has many functions

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

8. Modulation, Main Volume, Pan and Sustain Pedal

·       Control Change #1 Modulation

o   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

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

o   Like aftertouch, CC1 can modulate different properties of a sound but it is most commonly used to apply vibrato. It is also commonly used to change timbre or loudness

·       Control Change #7 channel volume

o   Most MIDI controllers have faders and knobs, which work well for CC7

o   CC7 is used to adjust the MIDI instrument’s output level

o   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

o   CC7 can also work well with an expression pedal that is connected to the MIDI controller

·       Control change #10 Pan

o   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

o   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

o   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

o   The pedal sends a CC64 along with only two states: on and off (pressed and released)

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

9. System Messages

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

o   System messages have no channel assignment

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

10. Sysex Exclusive and Timing Clock

·       System Exclusive

o   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

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

·       Timing Clock

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