Sitting at my computer the other night, right hand toying with knobs on my mixer, I suddenly realised that The Beatles had it wrong. It's not 'Revolver' — not a bad title, I suppose, but it should have been 'Evolver'. After all, music does evolve rather than being created in a single flash of inspiration. I believe the thought came to me as I tried to work out what happened to the piece of music I started to write a few hours earlier — it had disappeared some time ago, to be replaced by what I was currently listening to. Natural selection, evolutionary pressure, that's what happened to it.

At first there was a piano riff, emerging out of the primordial soup of a little improvisatory doodling. I could see a definite future for it as the basis of a moderately bouncy, guitar-led pop song — but a few hours later, it had somehow mutated into the theme tune to the next series of LA Law!

You know how it goes... you start off with a riff, a hook, some chords, or whatever; play with them, build on them. Riff begets Son of Riff, which makes Riff look a little passe, so out it goes. Son of Riff inspires you to add a bassline, which lends an unexpectedly dark mood to what you'd originally intended as a fairly 'up' piece. Then a friend pops round and points out that the drums suck. She's right. You change them.

Evolutionary pressure, you see? Unless you can hear everthing in your mind before you play a single note, developing a track is a process of continually trying possible variations on your current work in progress, and deciding which is 'best'. The better version goes on to be further modified, the loser is forgotten. The criteria by which you decide which is 'best' do, of course, vary. It may be down to your mood; it may be a collective band decision, with no single person in control; you may take the advice of a friend, producer, or collaborator; you may have a particular brief, and nothing but a folk/thrash metal crossover number (with lyrics about how children's TV isn't what it used to be) will do. However the decisions are made, the point is that they are, and the combination of the decision making process and your creation of chance-like variations gives a track an evolutionary life of its own. Here's to biodiversity, folks.

While we're on the subject of changes, evolution and such-like, this is my final issue as Editor of Sound On Sound — having spent almost three years at the helm of Europe's leading hi-tech music recording magazine, I feel it's time to move on to new challenges. Still, I hope to find the time to contribute the odd article now and again. I'd like to thank you, the readers of Sound On Sound, for helping make the magazine what it is today — it is your feedback that ultimately lets us know that we're on the right track.