Electro-Harmonix Pico Swello Attack Envelope

The Electro-Harmonix Pico Swello brings expressive volume envelope control to any guitar or bass rig in an ultra-compact format that fits almost anywhere on a pedalboard. Drawing inspiration from the renowned attack section of the EHX POG2, this pedal’s polyphonic attack envelope applies a smooth volume swell to every note you play, whether you’re picking single lines, arpeggios, or full chords, helping you achieve cello-like swells, ambient washes, and lush evolving textures without the need for fancy techniques or extra gear.

Equipped with intuitive four-knob controls — Volume, Attack, Frequency, and Mod — and a dedicated filter button that engages an adjustable low-pass filter with resonance, it’s easy to tailor the response and timbre of your swells from subtle legato styling to dramatic synth-style pad sounds. The compact Pico-sized housing delivers big-voiced, musical results while keeping your rig neat and flexible, and the included power adapter means you’re ready to plug in and play straight out of the box.