What Is MIDI?: A Beginner's Guide

MIDI is an acronym for musical instrument digital interface. This is an electronic language for computers and electronic musical instruments (e.g., keyboards and synthesizers), so they may communicate with a common standard. Most computers have a midi out port that can connect a computer to an external midi instrument. Also, most computers now have a soundcard and internal midi synthesizer that can play back midi files.
Midi files contain the equivalent of an electronic musical score. This digital sheet music contains performance information, without any actual samples of sound. Your computer or synthesizer contains the actual patches or samples of sound that are played for the midi score. MIDI computer software, such as Cakewalk, Cubase, Midisoft, Noteworthy Composer, or Finale, allows you to either compose music on screen through staff entry, or by playing music on a keyboard hooked up to the computer and recording this performance input.
Midi files can have multiple tracks, although older midi files often placed all the recording channels on a single track. Current software will easily split up the channels into separate tracks. One problem with midi is that different synthesizers use different sound patches/samples, so a file may not sound as good on some equipment as other equipment. The general midi file format is a useful attempt to minimize this problem.
Midi versus other sound formats. Midi is the only sound format that contains no actual sound samples. Microsoft .wav files, Sun au. files, Soundblaster snd. files, Roland .rol files, and other formats are real sound samples, and tend to be large files relative to the time duration of the sound, as compared to midi files. Music module files, such as .mod, .xm, .mtm., and .s3m, are actually a hybrid between the midi concept and sample formats. These contain performance information that refers to actual samples of sound that are used repeatedly in the playback of the file. These files are smaller than most .wav type formats, but larger than midi files.
Recently, sample formats have started to become smaller due to new advances in compression. Mpeg audio and Real Audio are examples of this. These formats require better CPUs and more memory on your computer than older formats, and they generally require a 32-bit operating system such as Windows95 or Win32's. For a thorough explanation about computers and sound formats, including a summary of the history of sound and the internet, visit this Computer Sound Information Page
What should one look for in a sound card? Clearly, the best cards offer wavetable synthesis, so that you can playback midi files with real sound and instrument samples for a more realistic sound. The Sound Blaster AWE 32/AWE 64 are highly regarded sound card of this type, due largely to the Vienna Soundfont technology they employ. Yamaha, Roland, Turtle Beach, and other companies also offer good wavetable synthesis cards. Due to lack of a common sound patch standard, some files will only sound best played back on certain sound cards. Of course, you'll need to spend more money for a better sound card, but if you're a big music lover or a professional musician you will find this worth it. For samples of soundcard output comparison, visit the Wavetable Vs. FM Sound Card Samples Page. For those unable or unwilling to purchase new sound cards, there is an exciting new option. Temporarily free and/or inexpensive software synthesizers are available for people with fast CPUs and non-wavetable sound cards. These produce wavetable sound using software synthesis. They include Wingroove, Roland's Virtual Sound Canvas, & Yamaha's S-YG20/Midi-plug. The Yamaha midi-plug is a Netscape/Internet Explorer plug-in that plays back midi using wavetable software synthesis.