MIDI

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MIDI

• Musical Instrument Digital Interface

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MIDI

• A data communications protocol that describes a
  means for music systems and related equipment to
  exchange information and control signals.
• MIDI is not audio signal
• MIDI represents the information needed to
  recreate a performance as many individual pieces
  of data.

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MIDI DEVICES

• Devices that can be controlled with MIDI include
• Keyboards
• Synths
• Effects units
• MIDI Interface/Control Devices
• Lighting Boards
• Mixers
• Computer Programs computers
• Fireworks

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MIDI EQUIPMENT

• MIDI Cable 5 pin DIN connectors
• MIDI Interface Multiple inputs and outputs
  which can digitally route MIDI Messages on the
  fly, much like a patch bay.

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MIDI PORTS

• MIDI IN
• Receives MIDI messages
• MIDI OUT
• Transmits MIDI
• MIDI THRU
• Makes a copy and passes through whatever comes
  into the MIDI IN

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MIDI SETUPS

• This is a typical MIDI/Computer setup.
• Additional devices can either be routed by the
  interface or connected to the MIDI THRU of the
  preceding device.
• Devices can be directly routed to one another
  without the need of a computer or interface

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MIDI CONTROLLERS

• Keyboard Controllers
• They look like a keyboard but may just only
  transmit MIDI information. No onboard sound
  creating engine.
• Wind Controllers, MIDI guitars, MIDI Drum sets.
• In a typical setup, the MIDI information will be
  transmitted to a sound module which receives the
  messages and performs the notes.
• Synthesizer terminology
• Monophonic/Polyphonic
• Keyboard Splitting split points
• Mod wheel
• Pitchbend
• Hold/sustain
• Volume
• Velocity sensitive
• Aftertouch Monophonic and Polyphonic

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MIDI CONTROLLERS

• Other Types of Controllers
• Numbered Controllers
• Continuous Controllers
• Mod Wheel
• Bi-directional Controllers
• Pitch Bend
• Switch Controllers
• On/off
• But what do all these things do to make sounds?

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MIDI MESSAGES

• MIDI uses binary code to transmit signals across
  the MIDI cable. This code informs the MIDI
  device receiving it how to act.
• There are 16 channels that any device can either
  send or receive to over one MIDI cable. Some may
  send and receive on several at once.
• Main Types of MIDI Messages
• Channel Messages
• Channel Mode
• Channel Voice
• System Messages
• System Common Messages
• System Real-time
• System Exclusive

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MIDI MESSAGES

• Channel Messages specify a particular MIDI
  channel within the message and generally control
  aspects of performance.
• Channel Mode are used primarily to select one of
  the four MIDI modes for a device.
• Mode 1 Omni On/Poly
• Mode 2 Omni On/Mono
• Mode 3 Omni Off/Poly
• Mode 4 Omni Off/Mono multitimbral
• Multi Mode - in Mode 4 each channel acts
  polyphonically up to the polyphonic capability of
  the device.

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MIDI MESSAGE FORMAT

• All MIDI information coded in bytes
• 7 data bits and 1 message type bit (MSB)
• MSB 1 means System Message
• MSB 0 means Channel Message
• 7 data bits range of values 0-127
• Messages sent in packets
• 1st Byte Status Byte has channel and type
• 2nd Byte data one
• 3rd Byte data two (some messages only)

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MIDI MESSAGES

• Channel Voice Messages
• Note On
• Note Off
• Channel Pressure (aftertouch)
• Polyphonic Key Pressure (aftertouch)
• Program Change
• Control Change affects parameters of notes that
  are already on. See MIDI 1.0 Detailed Spec.
• 127 different parameters.
• Continuous Controllers
• On/Off switch Controllers
• Data Controllers
• Undefined Controllers

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MIDI MESSEGES

• Most Important Controller Numbers
• 1 mod wheel
• 2 breath control
• 4 foot controller
• 7 main volume
• 64 sustain pedal
• 66 sostenuto pedal
• 67 soft pedal
• PitchBend
• Has much higher resolution, uses 14 bit resolution

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USING MIDI

• Common Messages, Industry Conventions, and
  General MIDI

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MIDI SYNTHESIZERS

• MIDI is Real-Time System
• Describes music in generic terms
• MIDI Synths interpret and realize
• All MIDI Synthesizers are different
• Different programs, or algorithms
• Different types of sounds with different controls
• All MIDI Synthesizers fundamentally the same
• All understand basic MIDI channel messages
• All allow user to select and play sounds by MIDI

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MODEL MASTER AND SLAVE

• Keyboard (master) sends MIDI messages on a given
  channel
• Synthesizer (slave) must be set to receive MIDI
  properly
• Mode Omni or Poly
• If Poly, then channel must be the same as the
  Masters
• Primary MIDI Messages
• Note On/Note Off
• Continuous Control (MW, Pedals)
• Pitch Bend
• Program Change

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NOTE ON/NOTE OFF MESSAGES

• A Note On msg is sent whenever a key is depressed
  on a MIDI keyboard
• Contains current output MIDI channel
• Contains MIDI note number of key pressed
• Contains Velocity with which key was hit
• A Note Off msg is sent when a key is released
• Should correspond to a preceding Note On msg
• Many companies use a 2nd Note On with velocity of
  zero, instead Yamaha, for example

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CONTINUOUS CONTROLLER MSGS

• Designed to allow dynamic control of synthesizer
  parameters, for example
• Volume Control
• Vibrato Speed and Depth
• Timbre Changes (Filtering, modulation)
• CCs are Channel Msgs with 2 data bytes
• Data Byte 1 controller (0-127)
• Data Byte 2 controller value (0-127)
• Optionally, MSB/LSB with CC 32

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PRIMARY RESERVED CC NUMBERS

• CC 0 Bank Select
• CC 1 Modulation Wheel
• CC 4 Modulation Pedal
• CC 6 Data Entry
• CC 7 Volume
• CC 10 Pan Position
• CC 64 Sustain Pedal
• CC 123 All Notes Off

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MIDI PROGRAM CHANGE MSG

• PC message used to change the sound on a
  particular MIDI channel
• Channel Message with 1 Data Byte
• Also called Patch Change message
• Patch comes from Modular Synths
• A particular way of connecting modules
• CPU a sound generation program
• Sometimes called a voice

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MIDI PROGRAM CHANGE MSG

• Available PC numbers 0 127
• Most manufacturers use 1 128
• Some synthesizers have only 32 programs
• Some have hundreds, divided into Banks
• Approaches to Using More Programs
• Bank Select (CC 0 and 32)
• Kurzweil PC 0-99 normal, 100-127 bank
• Bank Select or PC 100 must come first

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RECORDING MIDI DATA

• MIDI Sequencer
• Device or software program designed to record,
  edit, and play back MIDI data
• Many different types, made by many different
  manufacturers
• Typically modeled on multi-channel tape
  recorders multiple independent tracks
• Every company saves sequencer data in a
  different, proprietary file format

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INTRODUCTION TO CUBASE SX

• Manufactured by Steinberg
• DAW Software, like Nuendo
• Unlimited MIDI and Audio Tracks
• Recording, Editing, Mixing, Processing
• Support for Plugins Add-on Pgms
• Supports most Audio, MIDI interfaces
• Inter-application Communication via Rewire

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STANDARD MIDI FILES

• Extension to original MIDI 1.0 Spec
• Provide a standard format for storing MIDI
  Sequencer Data
• Three types of SMFs
• Format 0 1 multi-channel track
• Format 1 Multiple multi-channel tracks, track 1
  is tempo map for all tracks
• Format 2 Multiple tracks with independent tempos
  (not commonly used)

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GENERAL MIDI

• An industry standard set of sounds
• Grouped by families (8 sounds in each)

PC Family PC
Family 1-8 Piano
65-72 Reed 9-16 Chromatic Percussion
73-80 Pipe 17-24 Organ
81-88 Synth Lead 25-32 Guitar
89-96 Synth Pad 33-40 Bass
97-104 Synth Effects 41-48
Strings 105-112
Ethnic 49-56 Ensemble
113-120 Percussive 57-64 Brass
121-128 Sound Effects
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GENERAL MIDI

• Channels 1-9, 11-16 standard use
• Typically one sound per channel
• Polyphonic (multiple voices, same sound)
• Notes may sustain indefinitely
• Channel 10 is Drum Channel
• Each note number a different drum
• Most notes simply trigger
• Duration may be determined by velocity

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GM DRUM KITS

• Standard Kit (partial list)

Key Drum Sound Key Drum Sound 35
Acoustic Bass Drum 59 Ride Cymbal 2 36 Bass
Drum 1 60 Hi Bongo 37 Side Stick
61 Low Bongo 38 Acoustic Snare 62
Mute Hi Conga 39 Hand Clap 63 Open Hi
Conga 40 Electric Snare 64 Low Conga 41
Low Floor Tom 65 High Timbale 42
Closed Hi Hat 66 Low Timbale