MIDI (Musical Instrument Digital Interface) technology represents music in digital form. In this way you can create and fine-tune your composition one note at a time. You can also experiment with your composition in a way that’s never been possible before, until you get it sounding they way you want it. Imagine Mozart directing a symphony orchestra: “OK, all you violinists, put down your violins and pick up tubas. All you flutists, put down your flutes and pick up harmonicas. All you saxophonists, put down your saxophones and pick up that funky instrument that beeps and whines. Now play all your parts exactly the same but on your new instruments and we’ll see how that sounds.” After about 100 rounds of this, Mozart’s orchestra would likely either go on strike or tear him limb from limb, but a MIDI musician can easily do this, and a lot quicker and easier than Mozart ever could have.
Another advantage of MIDI is that with a MIDI sequencer you can record your music in easy-to-edit form. In this way MIDI technology towers of its predecessors the way a word processor towers over a typewriter. If you make a mistake while playing, you can fix it just like fixing a typing mistake on a word processor. If you can’t play fast enough to keep up with the tempo of a particular song then hey, slow it down to your own speed and then speed it back up whenever you wanna play it back, without any of the distortion that normally occurs when you try to speed up a musical recording using other technology.
MIDI’s major limitation is that it is very difficult to synthesize the human voice. Nevertheless, digital audio files are able to record your voice (although they are more difficult to manipulate should you wish to edit your pitiful howling into something a little easier on the ears), and MIDI files can be played in conjunction with digital audio files.