I built this pedal using a schematic found on Tim Escobedo's Circuit Snippets. The Bronx Cheer is an envelope waveshape filter. It's somewhat like a resonant VCF fuzz. The effect is very responsive to playing dynamics. It can produce high frequency synth textures, wacky fuzzy and odd bubbly tones on many different sources including guitar, bass, and keyboards. Take a listen to the Bronx Cheer.