Friday, February 26, 2010

MIDI Bootcamp - Part 1: Introduction


In this series of blog articles, I'm going to talk about MIDI, especially how I use it -- which may or may not be how others use it. This is mostly just stuff that I've figured out on my own, on the cheap. I'm by no means an expert, and I have no training that says "this is how you should use MIDI" (if such a thing even exists) so feel free to correct me in the comments if I say something wrong.

As a technical side note before we get started -- I do all of my work on a Windows PC. If you use a different OS (*cough*Mac*cough*), then I can't guarantee that anything I say about specific applications will work for you (technically, I can't really make that guarantee for Windows either). I can only hope that the general principles will still apply.

Why should I even care about MIDI?

First of all, it's true that nothing can quite match the sound of a real instrument being played well by a fine instrumentalist. What MIDI primarily brings to the table is a greater flexibility. You can simulate instruments that you could never own in real life, or even ones that don't exist. You can also clean up sloppy performances by fixing wrong notes, tightening up the timing, adding and removing notes, changing chords, dynamics, etc. An analogy might be the difference between using a manual typewriter compared to a word processor. The word processor allows you to go back after typing and change what you typed, the font, size, color, and so on.

What is MIDI?

MIDI means different things to different people. To many people, it means those horribly annoying sounds that start playing themselves when you visit certain websites -- especially at the end of the last century, before the general masses had the bandwidth to stream annoying mp3s. To other people it means racks of expensive electronics with names like Korg, Moog, and Yamaha, strung together with meters of cable...

No really, what is MIDI?

"MIDI" is an acronym that stands for "Musical Instrument Digital Interface". Let's see if we can unravel that acronym in reverse order (that's often a useful way to approach jargon).
  • Interface: This means that MIDI is a way of communicating between two pieces of technology (either hardware or software). Think of MIDI as a sort of language for programs and machines to talk to each other in.
  • Digital: This means that the MIDI language is expressed in numbers, as opposed to typical audio signals, which use analog waveforms.
  • Musical Instrument: This means that the things you can say in MIDI are things about about musical instruments. Specifically, about how an instrument is played.
Therefore, MIDI is a way to encode a musical performance into numbers that computers and other devices can manipulate to create sounds. For example, the MIDI data might have an instruction to play a middle C at medium volume. This allows you to decouple your performance from the sound generation.

The most important thing to know about MIDI is that it does not have any particular sound. It merely contains information about how an instrument was played. This information has to be converted into sound before it can be heard. The thing that does this converting is called a synthesizer. We'll talk more about those another time, but for now, realize that when people claim MIDI "sounds terrible" what they often mean is that the sounds created by the synthesizer sound terrible. This might sound like a minor distinction, but it's very important to understand the difference, because this is one of the keys to making MIDI "sound better" -- by realizing that MIDI doesn't actually have an inherent sound.

An Analogy

This is such an important concept, that I should probably give an illustration. Imagine an old player piano -- the kind that can play itself when you feed it a piano roll (a long spool of paper containing punch-outs which tell the piano which notes to play at any given time). Let's say your player piano is the most expensive, best-sounding piano in the world, and the piano roll performs an absolutely beautiful rendition of whatever music it's supposed to be.

Now take that same roll to an old, and poorly tuned piano, with a bad sounding tone, or maybe a kids toy piano (that's still capable of playing piano rolls for some odd reason). You couldn't say that the piano roll itself was bad -- you'd have to say that the piano that played the piano roll sounded bad. Of course, it's still possible to create a bad-sounding piano roll, even on the good piano, but in this case, that wasn't the problem. MIDI data is very much like a piano roll, and synthesizers are like the pianos that play them.

(Update: For your listening pleasure, here is Beethoven's Fifth Symphony on a player piano.)


MIDI is a technique that can add variety and flexibility to a mix, and is a useful tool to add to your bag of tricks. MIDI data captures a performance as a set of instructions to a synthesizer, but the actual sound produced depends on the synthesizer used. Thus there are two aspects to using MIDI: (1) creating the MIDI data in the first place, and (2) converting it to sound.

Next time, I'd like to start looking at synthesizers a little bit more, specifically, software synthesizers. If you have any questions or comments, or would like me to focus more on a given topic, let me know in the comments below. Thanks!

1 comment:

Covenant said...

C'mon Caleb... more more more!!!