Chromatic Sound to Light Conversion System. It's really that simple. Unlike so many of the sound responsive systems out there, ColorChord looks at the chromatic properties of the sound. It looks for notes, not ranges. If it hears an "E" it doesn't care what octave it's in, it's an E. This provides a good deal more interesting patterns between instruments and music than would be available otherwise.
Developed over many years, ColorChord 2 is now at the alpha stages. ColorChord 2 uses the same principles as ColorChord 1. A brief writeup on that can be seen here: http://cnlohr.blogspot.com/2010/11/colorchord-sound-lighting.html
The major differences in ColorChord 2 is the major rewrite to move everything back to the CPU and a multitude of algorithmic optimizations to make it possible to run on something other than the brand newest of systems.
TODO: add a link to the new video.
Here's a video of it running: https://www.youtube.com/watch?v=UI4eqOP2AU0
Currently, ColorChord 2 is designed to run on Linux or Windows. It's not particularly tied to an architecture, but does pretty much need a dedicated FPU to achieve any decent performance. Right now there aren't very many output options available for it. The most interesting one used for debugging is a vornoi-diagram-like thing called "DisplayShapeDriver."
There is work on an embedded version of ColorChord, which avoids floating point operations anywhere in the output pipeline. Though I have made efforts to port it to AVRs, it doesn't seem feasable to operate on AVRs without some shifty tricks which I'd like to avoid, so I have retargeted my efforts to 32-bit systems, such as the STM32F303, STM32F407, and the (somehow) the ESP8266. ColorChord Embedded uses a different codebase, located in the embeddedcommon and distributed among the various embedded* folders.
On Linux you'll need the following packages, for Debian/Ubuntu/Mint you'll need the following:
apt-get install libpulse-dev libasound2-dev libx11-dev libxext-dev libxinerama-dev libusb-1.0-0-dev
To make colorchord, type:
make
Then, to run it, use the following syntax:
./colorchord [config file, by default 'default.conf'] [any additional parameters]
If you edit default.conf while the program is running and resave it, it will use the settings in the newly saved file.