Theo handed over a crumpled bill. He was seventeen, desperate for a sound that was his own, and his current guitar—a beat-up Squier—only ever sounded like other people’s records.

Theo’s fingers tingled. He played a blues lick. The sound that came out wasn’t his. It was B.B. King’s exact vibrato, Clapton’s Woman Tone , layered like a ghost. The counter jumped to 3/1024. He played a metal riff—Dimebag’s squeal, Hetfield’s chunk. 12/1024.

Harder key presses trigger a brighter, more aggressive "pluck," while softer presses provide a mellow tone.