What are MIDI Files?
MIDI is the acronym for Musical Instrument Digital Interface. MIDI is a digital language that was agreed upon by major manufacturers of Electronic Musical Instruments. It allows keyboards, synthesizers, computers, tape decks and even mixers & stage-light controllers to communicate with each other. MIDIs are different than MP3s where MP3s have words and MIDIs are purely just music with no words.
A MIDI file contains what the composer did at his/her music keyboard. It keeps track of which note (key) was pressed, when it was pressed, for how long, and at what pressure. Playing back a MIDI file would need a device that can generate the sounds of common instruments on its own. MIDI files end with the extension .mid and MP3s end with the extension .mp3.
You can open MIDI files using a large number of software programs. Your sound card must support MIDI playback for MIDIs to work on your system. A MIDI file is just one musician's interpretation of a tune, and the files don't contain vocals. Also, MIDI files sound only as good as the equipment used to play them, so a cheap sound card will make the music sound tinny.
MIDI was introduced in 1983. It was developed in co-operation between the major music industry electronic instrument manufacturers including Roland, Yamaha, Korg and others. No one ever dreamed the kinds of sounds that could be created and accessed using such a powerful communications protocol.