The Electro-Harmonix Enigma is a powerful and precise envelope filter fine-tuned for bass frequency response. Sculpt your envelope to reveal a truly expressive tone, with a defined and unique signature. Enigma will deliver tight and smooth control over the complete 40 Hz to 3 kHz range, with a consistent and even sweetness. Need some edge? Engage Enigma's analog distortion and dial in anything from subtle bite to dominating crush. Enigma: a mysteriously musical envelope filter for bass guitar.