By Esh !
(C)1998 J. Eshleman,ll
Having given this lecture for many years and asked many times for it, I've created this
one-page intro to MIDI (Musical Instrument Digital Interface) as a printable web reference.
Think of MIDI as a "Player Piano"
Remember old player pianos ? MIDI is the modern player piano. That's why you can't just plug your CD player into your computer and convert music directly into a MIDI file... somebody has to play a MIDI keyboard and the info from that keyboard has to be recorded. What is recorded is not sound, it's info: which key, how hard, how long, etc. When the computer plays this back, it replays the note either on the keyboard that you created the files with in the first place, or on it's soundcard which has a synthesizer on a chip. MIDI is NOT sound ! It is the control commands for synthesizers.
Think of MIDI as a "CB Radio"
Imagine if you could take sixteen player pianos and make them all play in sync. Now make each piano sound like a different instrument. That's what MIDI does. Just like a CB Radio, you can communicate to your MIDI device on sixteen channels and tell each channel what instrument you'd like for it to play. Remember the "trucker's channel" on CB's used to be 19 ? Well, the "drummer's channel" in MIDI is channel 10. It is different from the other channels in that each NOTE on this channel plays a different drum. All other channels usually have one instrument which plays on all notes. Computer programs and hardware devices which record MIDI are called "sequencers". They have "tracks" like multi-track audio recorders that allow you to record your music track-by-track. Each track can then be given a channel and an instrument to play that music back on.
What Do I Need to Create MIDI Files ?
If you're reading this, you probably already have a computer. It should have a good quality soundcard (one with wavetable synthesizing such as the Creative Labs AWE 32 or 64, Ensoniq Soundscape, etc.). There are MIDI interface cables made especially for soundcards that plug into the joystick port and are inexpensive. If you don't have a soundcard, or simply want a more reliable interface, you can buy a dedicated MIDI interface for your computer. I have used the PC Card and the parallel-port midi interfaces by Music Quest and Altech Systems and they work fine. I do not recommend serial port interfaces, which have caused me problems in the past. You'll need a sequencer program to create the MIDI files (Winjammer (shareware) Master Tracks Pro, Power Tracks Pro, Cakewalk, Cubase, Ballade, to name but a few). Now, once you get this, you can create midi files by selecting musical notes from your mouse and placing them into scores... but by far, the best way is to use a MIDI keyboard. Connect the MIDI OUT of the keyboard to the MIDI IN of the computer, and the MIDI OUT of the computer to the MIDI IN of the keyboard.
What is General Midi (GM) ?
GM is a standard set of 128 instruments and controllers and is close to universal in both keyboards and soundcards. Songs in the alt.binaries.sounds.midi newsgroup and files you create using this keyboard will playback on any other GM keyboard or soundcard.