15 MIDI - MTSU Comps

Timing Clock

As previously mentioned, System messages under the Real Time category are used to synchronize clock-based MIDI devices, such as keyboards that have a built-in sequencer, drum machines and MIDI sequencers. These devices follow a tempo during playback and recording. If your network has two or more of these devices, Timing Clock will assure their tempos lock together.

Workstation keyboard

A keyboard that can generate, receive midi, has a full keyboard, and can generate sounds onboard to it.

Pitch Bend

A pitch bend control allows a MIDI keyboard controller to do expressive techniques commonly heard from vocalist and instrumentalists.

MIDI Tone Module

A sound module is an electronic musical instrument without a human-playable interface such as a piano-style musical keyboard. Sound modules have to be operated using an externally connected device, which is often a MIDI controller, of which the most common type is the musical keyboard.

Step Sequencer

A step sequencer is a sequencer that operates by dividing a measure into a pre-determined number of divisions, or "steps." Each step can then trigger notes, send a voltage, control a parameter value, or trigger or control other events

MIDI Controller

A type of MIDI device that generates and transmits MIDI messages but does not typically receive MIDI messages and does not generate an audio output.

MIDI Instrument

A type of MIDI device that receives MIDI messages and generates an audio output. The device may generate and transmit MIDI messages but its sole purpose is to receive and playback MIDI messages.

Velocity Sensitivity

A velocity-sensitive keyboard will measure the different velocities of your notes. In other words, it will measure the speed at which you strike a key. For instance, a faster (harder) strike will produce a higher velocity level. This typically produces a louder note. A slower, softer attack typically yields a softer note.

Program Change

Also known as Patch Change, a type of MIDI message used for sending data to devices to cause them to change to a new program. Program Changes messages are channelized so they will only affect a device on a specific MIDI channel.

MIDI Thru

MIDI THRU - This port is used to retransmit (forward) a copy of every MIDI message received by the MIDI device's IN port.

MIDI Cable

MIDI messages have to travel from one physical device to another within a network, which may or may not include a computer. These messages travel via MIDI cable between MIDI devices (not including a computer). When a computer is added to the network, other protocols such as USB, FireWire or Ethernet may be incorporated. For now, let's discuss the MIDI cable. A MIDI cable comes in various lengths (a maximum of fifty feet recommended) and uses a unique DIN male plug at each end with five pins (for this reason, using a MIDI cable is sometimes referred to as MIDI DIN). Pins four and five connect the plugs at each end with a shielded twisted pair wire. Pin two is connected to shield (for eliminating interference) and pins one and three are not connecting to anything (see figure 2.3). Almost twenty-five years ago, Craig Anderton stated a speculation in MIDI for Musicians that pins one and three would be used someday as MIDI evolved. At the time of this writing, they are still not used!

MIDI USB

MIDI transmitted over the USB protocol

Monotimbral/Multitimbral

Mono timbral can only play one channel at once, multi-timbral can play multiple channels at once

PPQN

Pulses per quarternote

MIDI Ports

The 5-pin DIN plug on each end of the MIDI cable plugs into one of three different MIDI ports on a MIDI device: THRU, OUT, or IN. MIDI OUT - This port will transmit MIDI messages that originate in this MIDI device. MIDI IN - This port will receive MIDI messages for this MIDI device. MIDI THRU - This port is used to retransmit (forward) a copy of every MIDI message received by the MIDI device's IN port.

MIDI Modes

The MIDI spec defines four modes that are combinations of Omni (on/off), Poly and Mono. Omni means all. If Omni is switched on, the MIDI instrument will respond to all MIDI channels no matter what its RX channel is set to. If Omni is off, the MIDI instrument will respond to only one MIDI channel. If Poly is selected, the MIDI instrument will playback simultaneously received notes (polyphonic). Differently, if Mono is selected, it will playback only one note at a time (monophonic).

Control Change

The first half of the status byte is 1011 and the second half is assigned to MIDI channel 16. The first data byte defines the control number (also referred to as the controller or cc#) and the last date byte defines the value for the control number. In this example, the control number is 0 and the value for the control number is 64. (a) 1 0 1 1 1 1 1 1 - 0 0 0 0 0 0 0 0 0 - 1 0 0 0 0 0 0

Hexadecimal Number System

The hexadecimal numbering system has 16 digits (base-16). They are: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F. I suggest you think of A as 10, B as 11, C as 12, D as 13, E as 14 and F as 15.

MIDI DIN

The kind of connector used for MIDI cables and receptacles.

Status Byte/Data Byte

The status byte is the portion of a MIDI message that defines the type of information being sent. Data bytes have different interpretations depending on its status byte. The distinguishing feature between data bytes and status bytes is the most significant bit (MSB) or the left most bit of the binary eight bit number. The MSB of all data bytes is zero and the MSB of all status bytes is one. The MSB determines the range of values for each type of byte. You'll always use two hex digits for a status byte and usually use decimal numbers for the data bytes.

MIDI Channels

This includes messages such as Note-On, Note-Off, Program Change, etc. (we will cover all these messages in detail in chapter three). Within all channel messages, four bits are used to address the message to a channel. In other words, each message has a channel assignment. Since four bits are used to define the channel, there are 16 possible channels: 1 through 16.

Daisy Chain

To daisy chain a MIDI controller and two modules, connect a MIDI cable to the thru port of tone module 1 in order to forward MIDI messages to module 2.

System Exclusive

Universal System Exclusive Messages are defined as Real Time or Non-Real Time, and are used for extensions to MIDI that are NOT intended to be manufacturer exclusive (despite the name).

Star Network

a network of midi devices created by using multiple midi splitters

Virtual Instrument

a software instrument that receives MIDI and transmits audio.

Local Control

a switch that allows you to connect and disconnect the keyboard on the MIDI controller from its internal sound engine. It is typical to disconnect while MIDI sequencing with a computer.

Binary Number System

has only two digits: a 0 and 1 (it is also called base-2). A single digit, a 0 or 1, is referred to as a bit. Four bits are referred to as a nibble (e.g. 1001) and 8 bits are referred to as a byte (e.g. 10101010). Any other amount of bits is referred to as a word. For example, 11011 is a 5-bit word.

Polyphony

many notes at one time

Channel Aftertouch

refers to the average amount of pressure applied to whichever keys are held down; it is independent of which key or how many keys are held.

MIDI Quantization

the process of locking the start and end of midi notes to a grid in musical time, represented in Ticks

MIDI Sequencing

the recording, editing and playback of MIDI in a multi- track environment

Polyphonic Key Aftertouch

which allows each key being held to transmit a separate, independent aftertouch value. While polyphonic aftertouch can be extremely expressive, it can also be difficult for the unskilled to control, and can result in the transmission a great deal of unnecessary MIDI data, eating bandwidth and slowing MIDI response time.

MIDI Merge

A MIDI merger is able to combine the input from multiple devices into a single stream, and allows multiple controllers to be connected to a single device.

MIDI Messages

A MIDI message consist of one, two are three bytes. The first byte is a status byte and any following bytes are data bytes. For a status byte, the most significant bit (MSB) is 1, and for a data byte, it is 0. Figure 3.6a is an example of a MIDI message in binary. The first byte is a status byte (MSB = 1), the following two bytes are data bytes (MSB = 0).

General MIDI

General MIDI was introduced in 1991 to address the issue that the MIDI spec did not assign specific sounds for program change numbers. Without GM, sending the same program change number to different MIDI instruments may call up different sounds. For example, program change number 1 (transmitted from a MIDI controller or a MIDI sequencer) may recall a piano patch on one instrument but a kazoo patch on a different instrument. There are a lot of differences between a piano and a kazoo! However, is both of the instruments were GM-compatible, you could guarantee that patches would be the same type of patch.