Understanding MIDI

The Musical Instrument Digital Interface, better known as MIDI, is a technical standard used to help a wide variety of musical instruments communicate with digital devices. First standardized in 1983, MIDI protocols have grown increasingly essential as music production moves towards a primarily digital model. For home recording enthusiasts, MIDI protocols translate music being played on an instrument or controller into a digital file that can be played, edited, mixed and mastered in Pro Tools and other recording suites.

MIDI protocols have become so commonplace in the home recording world that it can be easy to take them and the devices on which they run for granted. However, getting the most out of a powerful tool like MIDI means understanding how to best utilize it in a variety of recording situations. As with all musical skills, the first step towards mastering MIDI is understanding the technology and its applications.

Understanding MIDI

Almost every home recording enthusiast has used MIDI protocols to complete editing tasks. MIDI devices are connected to computers or mixing boards via a link that can carry 16 signal lines. The device uses each of these lines to send messages to a computer that are then translated into digital notes or actions. All MIDI devices use this same protocol. However, there are significant differences between MIDI instruments and MIDI controllers.

MIDI instruments are simply those instruments that can be plugged into a computer or digital mixing board in order to be recorded. With these types of instruments, a signal is sent via the MIDI interface anytime a note is played. This note is then captured by a digital recording studio, where it is placed in sequence with all other parts of the same composition. The MIDI protocol facilitates this quick-and-easy communication between instruments and digital devices, eliminating the need for bulky recording equipment.

MIDI controllers use the same protocols as MIDI instruments, but they are put to different purposes in a recording studio. These devices, which often look like mixing boards, drum machines and small keyboards, are used to control actions in a recording program. These controllers are often used to set and control tempo and to control basic recording parameters. Most MIDI controllers work seamlessly with the Mac interface and Pro Tools.

How is MIDI Used?

Both home and professional music producers can utilize MIDI protocols to create and manipulate music. Those who need to record live instrument playback can do so by connecting MIDI-capable instruments to digital recording devices. As the instrument is played, MIDI signals register a note in the recording device. Because each note is recorded individually, musicians can easily correct mistakes and adjust playback in the Pro Tools timeline.

MIDI devices are also used to trigger actions in a recording suite. With synthesizers, MIDI signals simply trigger a certain sound bank file stored on a computer or memory card in order to create different components of a song. Other controller devices are used to send function-related signals to Pro Tools. These devices often adjust tempo and pitch and add special effects to tracks.

Some of the most common MIDI signals, known as messages, include:

  • Note On, sent when a musician first presses a key on a MIDI instrument.
  • Note Off, sent when a musician releases a key on a MIDI instrument.
  • Pitch Wheel Change, which indicates a shift in the pitch of the recording.
  • Control Change, sent when a musician manipulates a control parameter using the MIDI device.

Why Use MIDI Protocols?

Musicians who are new to home recording may wonder why it makes sense to use MIDI protocols instead of simply recording instruments and vocals into a traditional mixing board. After all, recordings from a mixing board can generally be imported into Pro Tools and other music editing programs. However, editing flexibility is lost when recorded files are imported into Pro Tools because much of the individual note data is lost.

When using MIDI protocols, recording enthusiasts eliminate the problem of data loss. Every individual note is captured, meaning that each individual note can be moved or altered as needed. Musicians can also alter all of the parameters attached to each note in a way that is simply not possible with traditional instruments. For example, say a musician wants to change the key of a song from C major to E minor.

Applying a filter to an existing recording may distort the sound quality. With MIDI files, changes to recording parameters can be made retroactively, meaning that the note will not be distorted when undergoing a parameter change. Instead, the song will behave as though it was originally played according to the new parameters. This provides for the utmost in convenience and flexibility.

Of course, MIDI protocols are also preferred by musicians of all experience levels because they are used around the world. Any MIDI device can be connected to any MIDI-capable digital recording or playback interface in order to complete recording tasks. It’s important to remember that while MIDI protocols are used worldwide, MIDI itself is not a file format like MP4 or ACC. MIDI files store message strings that can only be interpreted by recording programs and MIDI-compatible playback devices.

MIDI Devices and Controllers

Any device that utilizes MIDI protocols to exchange music data can be considered a MIDI. These devices fall into one of two categories. The first of these types of devices are recording suites and digital soundboards that receive and interpret MIDI messages in order to create music files. Pro Tools supports MIDI protocols, meaning that MIDI devices can be recorded directly into the program. Digital mixing boards that offer MIDI support are often used both in recording and in live performance because they offer real-time playback of MIDI messages.

The second group of devices are instruments and controllers that send MIDI messages to recording programs and digital mixing boards. Many different MIDI instruments and controllers are available on today’s market. Among the most popular are synthesizers, which offer unlimited options to consumers because they can trigger absolutely any sound in the world so long as it has been saved in the device’s sound bank. Other controllers, such as drum pads and keyboards, can be used both to trigger instruments and to trigger actions in Pro Tools.

MIDI protocols offer lightning-fast translation of musical data from instruments and controllers into recording programs and mixing boards, making them one of the most invaluable tools of the contemporary recording enthusiast. Without MIDI protocols, home recording enthusiasts in particular face data loss and an inability to truly manipulate and master their tracks. The simple addition of MIDI devices to a home recording studio can improve workflow while allowing for real creative flexibility.

Resources:

http://www.midi.org/
http://www.midi.org/techspecs/midimessages.php
http://entertainment.howstuffworks.com/midi1.htm
http://www.computerhope.com/jargon/m/midi.htm
http://www.instructables.com/id/What-is-MIDI/