The HeadRush Envelope Filter is a stompbox format pedal that produces an envelope filter effect, the dynamic, auto-wah family of sounds covered on the site's filter pedals page. HeadRush describes it as "Based on a DOD® FX25 Evelope Filter," meaning the circuit takes the DOD FX25 envelope filter as its reference design1.
An envelope filter responds to how hard you pick: the pedal sweeps a filter across your signal in time with your attack, producing the vowel-like "quack" players associate with funk rhythm parts and wah-style sounds, but without needing to rock a treadle the way a wah pedal does.
Key facts
What it does
HeadRush lists the pedal under its Stompboxes range as an "Envelope Filter"1. As a filter effect, it shapes the tone of the guitar or bass signal rather than adding time-based effects such as delay or reverb, and it sits alongside related dynamic and tone-shaping pedals like compressors and equalization pedals on a board.
The DOD FX25 that the circuit is based on is a classic envelope filter design, and HeadRush's use of it as the reference points to the pedal being aimed at players who want that style of touch-sensitive filter response in a single stompbox1.
Videos
Digital Guitars UK
Sources (1)
- HeadRush Envelope Filter product page, HeadRush, 2026
