Totally a thicker sound. Also, the audio was recorded with my camera instead of via my computer. The schematic changed slightly from the prototype to the real thing -- I removed the resistor and a capacitor because I found I could get similar sounds and it was slightly easier to build.

I kind of want to make one where you can switch between different capacitor values discretely, but I also really like the idea of having it be super-compact. Maybe the best middle road would be to make a few with different configurations, and allow them to act as filters on each other?

Hah hah -- it would actually be a significant change to the idea. Instead of just an output jack, there'd be an input as well. That way I could chain them in weird ways and allow them to act as instruments/effects simultaneously.