Introduction to Music Production 8 – MIDI

Introduction to Music Production 8 – MIDI

MIDI is short for Musical Instrument Digital Interface, a technical standard that describes a protocol, digital interface, and connectors.  It was developed as a means of communication between devices, initially synthesizers.  MIDI does not send audio signals, but instead sends control data.  It can send note on/off, velocity, MIDI Note/Control Channel, and channel data.  It is a very low memory method of controlling studio hardware and software.


MIDI first arose in 1981 when Dave Smith of Sequential Circuits presented a paper on a universal interface for synthesizers.  It was co-developed with other companies (such as Roland), and made its first major debut at NAMM in 1983.  Dave Smith’s goal was to create an interface so simple, inexpensive, and foolproof to implement that no manufacturer could refuse.  An identical 5-pin cable design has stayed with MIDI since its inception.  MIDI has a resolution of 128 values for all of its parameters (notes, velocity, pitch bend, etc) where 0 is the lowest and 127 is the highest.  It does not send continuous signals, but instead sends messages when changes occur (i.e. note on/off; knob value change from 110 to 127).

In Hardware

In hardware, MIDI is implemented as a means of control.  It be used to send control signals from one piece of software or hardware to another.  There are three port configurations for cables: In, Out, and Through.

IN: This is where you will plug in an external device to be in control.

OUT: This is where you plug a cable to control another device.  It outputs the data.

THROUGH (THRU): This takes the signal passed to the IN port and passes it THROUGH to another device’s IN port.  It allows you to control multiple devices with the same signal.

Most modern audio interfaces have MIDI In/Out, but many modern devices can send the same signal over USB, Firewire, and Thunderbolt cables.  Non-musical devices may control and be controlled by MIDI as well, including visual software, hardware mixing boards, and various other controllers.


In Software

In most DAWs, MIDI is used to write notation for software instruments using a piano roll, named after the old player pianos.  In piano rolls in a DAW, users may write notation for a MIDI-driven instrument based off of the typical bar/beat subdivisions found in music.  Piano rolls also allow users to assign velocity (the strength at which a note is hit/pressed), pitch bend, and other control parameters that a user may automate.  On the left hand side, you will usually find a standard piano keyboard.  The pitch will go from bottom to top, the bottom being lower pitches.  Velocity per note is usually a separate section, sometimes in a separate menu.

Piano Roll


  • Low Latency
  • Very user friendly and easy to use
  • Most hardware and software audio devices can use it
  • It can be sent over many forms of media (ethernet, usb, thunderbolt, firewire, and more)
  • Up to 16 channels can be sent over a single cable


  • Does not carry audio information
  • MIDI messages cannot be sent simultaneously on the same channel, so each message adds a bit of latency (approximately 1 millisecond per MIDI note/message)
  • Some devices do not contain all types of ports, or any at all