Tech Tip:What is MIDI?: Dr. Digital Explains
How MIDI Works/How It Works and What You Need To Know
So what is MIDI, and why is it such a popular and important part of making music today?
MIDI, short for "Musical Instrument Digital Interface," was created almost twenty years ago so that keyboards by different manufacturers could communicate with one another. Initially it was used to help create layered keyboard parts and to store and edit patches (the locations where sounds are stored) between devices. As the technology developed, MIDI proved to be an excellent and efficient means of recording and playing back musical performances. This last aspect has become the most prominent use for MIDI in the last fifteen years or so.
What MIDI Does
Here's where you say, "Wait a second. Digital information? So using MIDI is the same as recording guitars or vocals on my computer?" No! See, MIDI information isn't sound (audio) on its own -- it tells an instrument what notes to play and which sounds to make. You always need to have some sort of MIDI sound module as a sound source to play back MIDI information. You can't actually hear MIDI on its own as you can with digital audio.
With MIDI you can also change the timing of individual notes by quantizing, alter the dynamics of the performance by changing velocity and adjust many other aspects of a performance. Best of all, you can choose or alter the sounds right up until the mixdown process. If you play a part using a harpsichord sound and then decide you'd rather hear it on an organ, a clavinet, or any other sound imaginable, the change is just a few clicks away.
Current MIDI implementation allows for 16 separate "channels" of MIDI to be transmitted over a single MIDI cable, which generally means that 16 different sounds or parts can be played back at the same time from a single MIDI sound module, if the module can handle it. (Most MIDI data takes the form of a number between 0 and 127 translated into hexadecimal form using the numbers 0 to 9 and the letters A to F. But let's save that for another article.) You can see that you wouldn't need many sound modules at all to have a veritable MIDI orchestra at your command.
No doubt about it, MIDI has had an enormous impact on the recording industry. It's used in the smallest home setups and in the world's most sophisticated studios. At this point, it is one of the easiest and most versatile means of creating musical arrangements.
Keep an eye on this section to learn some of the ways you can use MIDI to alter your performances, and how MIDI can make your life a lot easier.