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Monday, June 29, 2009

Producing Natural-Sounding MIDI Notes

When making electronically-produced music, you'll find yourself often programming notes rather than playing them. People who don't understand the medium will say that this makes the music cold, mechanical and lifeless, but they simply don't understand the amount of work and craftsmanship that goes into manually arranging notes. A composer needs to take into account very precise attributes of every note of every measure of every part they program. This can be very daunting. When I write melodies that are more complex than I can feasibly play, I'll use Cubase's piano-roll style grid to place notes, and then I'll let the computer play them. In the early days, this usually meant that the notes sounded harsh and machine-like. How do I fix this? How can I make MIDI-generated tones sound more natural to the listener?

Well, I thought, human hands are not machines. We don't hit every note on precisely the right beat, right? After placing my notes, I would nudge them just slightly out of sync with the rhythm. Hopefully this would be the subtle change needed to make the music sound more organic. Right?

As it turns out, the hands of a trained musician actually have excellent rhythm; better than you would ever expect. Once I'd learned to play piano with some moderate skill I found that my own notes pretty much hit precisely on the beat when needed. My nudging of the MIDI tracks only served to make my melodies sound amateur and unrefined.

No, the key to lifelike melodies, I found, is in the velocity of the notes played. With some exceptions, almost all of your machine-played notes can be placed in perfect sync as long as they have heavily varied velocities. Velocity, in this case, means how hard the note is played. Think of the difference between a piano being played softly and a piano being played loudly and you'll know what I mean.
I could spend several paragraphs describing the method to you, but I'll let this picture do most of the talking:

As you can see in this very generic guide, the odd-numbered notes are louder, while the even ones are quieter. You can also see that there's a more subtle pattern of general volume change: The smaller the note (8th, 16th, 32nd etc.) the more likely it will be relatively quiet when it is not on the main beats of a measure.

When making a melody, I will start with this pattern and then adjust it according to what I want it to sound like for that particular part. Following this pattern works particularly well for complex melodies with many notes.

If you simply follow that chart to the letter, your melody will still have a machine-like quality to it. It's best to arrange your velocities in this pattern and then adjust everything a little afterward, putting emphasis on certain notes for dramatic effect. This particular chart, for example, is clearly skewed towards something that emphasizes beats on 1 and 3, which you don't alway want. Try adding a little randomness too and see how it comes out. The beauty of MIDI-generated music is that if you don't like it, you can endlessly tweak it until it sounds perfect.

Do you have any cool techniques for MIDI melodies?