Okay, it's New Year's Eve, I'm overdue to write this week's Web log entry, and the topic I wanted to write about is held up because of (among other things) a package that apparently was stolen from my front porch after it was "delivered" during my vacation and I told them not to mail it so early but blah blah blah... Instead of the exciting mystery topic, let's dig into the back catalog again and think about how to listen to the Mandelbrot set.
If I'm trying to build up a sound by additive synthesis of sine-wave partials and I want it to sound interestingly unlike what people expect of music, then maybe I want to make the partials as much not harmonic as possible. Assuming I can somehow define that in a rigorous enough way to actually know when I've achieved it.
The Leapfrog VCF does not actually go "ribbet," at least not without some effort. But after being told by one friend I showed it to that most people don't want to make real music on their modulars but just want something that goes "uuuuuuuuuuuLAAAAAAAAAAAAARGH" (which, let's face it, is true), I've added a demo highlighting that. Uulargh? Yeah, we've got this.
You've probably noticed that although resistors and capacitors come in many different values, some of which seem like they could be randomly chosen, there's nonetheless some sort of logic to it. You'll see power-of-ten sizes like 1kΩ, 10kΩ, 100kΩ and it's understandable that those would be "round" numbers it might be convenient to use and manufacture... but for instance there also seems to be something special about the number 47, so you see many resistor values like 4.7kΩ, 47kΩ, 470kΩ, and capacitors like 0.47µF and 470pF. Why 47? Why not 46 or 48 - especially when 47 is a prime number and 48 has many small divisors, which would seem more useful? Here are some notes on the commonly-used numbers and where they come from.