This filtering comes from using the PVOC utility and opcode in Csound. When I first heard this technique in Room 12 at the UW back in 1997 I was blown away. I had never heard anything like it and wanted to explore, but it took SO LONG to analyze long files to be resynthesized this way. I sculpted this sound from an old experiment (from 2004 wow) that analyzed me playing E, G and A on the low string of my guitar, where I control which frequency 'bins' are used in replaying the original. The "bins" here represent linear slices of the frequency spectrum, so you might play bin #3 from the analysis, and you only hear the original signal from 150-200 Hz. I assigned the bins to keys on my keyboard and improvised, then promptly forgot about the experiment. Soon I will process some coyotes, assign their songs to keys on my keyboard, and my dog will freak out.