33. MIDI System Components

Three groups of components are commonly found in a MIDI-based system. These groups are:

1. Instruments that are "played" and send MIDI information to other instruments in the system. These are often referred to as MIDI-controllers, with the keyboard controller the most common.

Diagram 33-1: A keyboard controller.

2. Instruments that receive and respond to MIDI information. Instruments in this group take several forms, with sound-producing modules being most central to a MIDI system. This second group, however, may also contain instruments that add reverberation, or instruments like mixers that combine sounds that originate from several sound sources.

Diagram 33-2: A sound module.

3. Instruments that can record, edit, and play back MIDI information. These are commonly called sequencers. A MIDI sequencer is either a hardware device programmed specifically to record, edit and play back MIDI data, or a software program in a computer that carries out these same tasks.

Example 33-3: MIDI data is received by sequencing software where it can be recorded, edited and ultimately transmitted to sound-producing components in the MIDI system.

Very often manufacturers combine these three components into one physical instrument or software unit. It is possible to find a single instrument that includes a keyboard controller, some sort of sound-producing synthesis engine, and a sequencer.

An instrument is said to be a MIDI instrument when it is able to transmit or receive, and to understand, MIDI data. In fact, a published set of MIDI specifications agreed upon by manufacturers allows instruments from different manufacturers to communicate with one another. One of the great strengths of MIDI is that as long as a manufacturer adheres to the MIDI specifications any MIDI instrument can communicate with any other MIDI instrument.

These three groups of components form the foundation of a MIDI-based system.