I was flipping through the latest winter 2009-2010 issue of 2600 magazine the other day on my way up to a family vacation and an article caught my eye. The author of the article, SigFLUP, had written a program to use your computer keyboard to manipulate a looping wav file. After installing SoX & libSDL I fired up the program with the test loop that was provided.  The author posted a demo of what kinds of variations could be made on one loop.

The program is packaged in the form of a one-size-fits-all shell script that has C embedded in it which compiles at run time. It took a little bit to start up in my Debian VM. I’d say 20-30 seconds.  Once it fired up, I was presented with a blank window that had spawned from the terminal.  That’s when you know it’s ready to run.

I’m not entirely clear to me how the program runs but from the article in 2600 it seems that it maps the 16-bits of the wav to QWERTYUI & ASDFGHJK with Q being the least significant bit and K being the most significant bit.  To use the program, you press two or more of these keys.  What the program does is replaces the values in all of the bits you are pressing with 1 if any of the bits you are pressing are set to 1.  In other words, if you press QWE and the values of QWE were 001, the values of those would then become 111.  All of the other values remain the same.  As you can imagine, this leads to sound crazy sounds.  Listen to the demo to see what I mean.  SigFLUP says in the article that the loop should be a multiple of 65535 samples in length but if you are just going for effects that you can export to your sound editor, that doesn’t matter too much.  Don’t miss the pitch bender keys which are “Z” & “X”.

The program understandably has a few glitches or I just don’t know how to use it right, but nevertheless it makes for a really cool proof of concept that I would love to expand upon someday.  You can download the program here from SigFLUP’s site.