The Electro-Harmonix PICO Swell-O distills the fan-favorite attack envelope feature from the legendary POG2 into a standalone pedal. With polyphonic swell effects and a modulated low-pass filter, it transforms your playing with expressive, atmospheric textures. Whether you're crafting lush ambient pads or adding smooth, legato transitions to fast runs, the PICO Swell-O offers unprecedented control over your instrument’s attack and filter behavior—all in a compact Pico-sized chassis.

Polyphonic Attack Envelope Creates Expressive Swells

This pedal uses a polyphonic attack envelope that applies swelling to each note individually, even within a chord. The attack control adjusts how quickly the swell happens, ranging from fast, gentle articulation to long, drawn-out volume increases. This feature lets guitarists add movement to arpeggios or create lush pad effects. By shaping each note’s onset, the unit helps players achieve a more fluid and expressive sound during fast runs or slow ambient builds.

Modulated Low-Pass Filter Expands Sonic Possibilities

A dedicated low-pass filter section, activated by a single button, introduces resonance and envelope modulation. The FREQ knob sets the cutoff point, letting users focus on high or low frequencies. The MOD control selects the depth and direction of the filter sweep, with timing tied directly to the attack envelope setting. This design makes it easy to blend classic filter sweeps with evolving swells, enhancing the musicality of the effect and providing access to both subtle and dramatic changes in timbre.

Simple Control Layout Streamlines Setup and Tuning

The pedal’s layout includes four knobs: VOL, ATTACK, FREQ and MOD, plus a filter button for resonance settings. Turning up ATTACK lengthens the envelope, while VOL compensates for perceived volume loss during slower swells. The controls respond quickly, making on-the-fly changes during practice or performance straightforward. With all key features on the top panel, users adjust parameters without digging through menus or secondary switches, maintaining focus on their playing.

Compact Build Supports Durability and Portability

Electro-Harmonix built this unit using their Pico chassis, designed for reliability in a small footprint. The enclosure is sturdy, with robust jacks and a power adapter included for consistent operation. The compact design saves pedalboard space, while the components withstand the rigors of transport and repeated use. This approach ensures players can rely on the pedal for regular gigs and studio work without worrying about wear or connection issues.

Player Experience With Pico Swello Attack Filter Effects Pedal

Musicians interested in evolving ambient sounds, synth-like pads or smooth lead lines will find this attack filter pedal useful for shaping every note’s character. The integrated envelope and filter controls give precise command over swells and tonal shifts, helping players sculpt unique textures and transitions in real time. This model rewards creative experimentation, allowing users to build distinctive soundscapes that stand out in recordings and live sets.