Electronic Audio Experiments Prismatic Wall

The Prismatic Wall is a sympathetic resonator pedal from Electronic Audio Experiments that takes your incoming sound and transmutes it into the vibrations of a modeled bank of strings. The maker describes it as part reverb and part synthesizer, with "metallic yet warm timbres" that "span from the subtle harmonic aura of a third bridge to the rich chromatic suspensions of a grand piano"¹. Where a reverb pedal recreates a space, the Prismatic Wall recreates strings: it listens to what you play and answers with tuned resonances, the way the sympathetic strings of a sitar or a Hardanger fiddle ring behind the notes you actually play.

Under the hood it is an analog/digital hybrid. The digital side uses a physical string model built from tuned delay lines, with tuning achieved by varying the sample rate of the system, running at 24 bit resolution. That is paired with analog filtering and emphasis, and a high headroom analog dry path and mixer keeps your original signal in the analog domain¹. Guitar Pedal X called it "a really unique and rare variety of Modulator - a Sympathetic Strings / Resonator / Synthesizer / Reverberator" in its 2024 round-up of the year's best new modulation and utility pedals².

How it works

The core idea is sympathetic resonance. Instead of processing your signal with a reverb algorithm or a delay line, the pedal drives a bank of virtual strings that are tuned to a musical structure you choose. Your dry signal stays analog, and the resonator bank responds to it, so chords bloom into ringing harmonic clouds and single notes acquire a metallic halo behind them. The Drive control sets how hard your signal pushes the resonator, and at higher settings it overloads, which changes the character of the excitation rather than simply making it louder¹.

Because tuning is done by varying the sample rate of the digital system, the pitch of the whole string bank can move continuously across a four octave range with the Tune control¹. This is also what makes the tuning modes possible: the same string model can be retuned to different interval structures, from a single fundamental with harmonic overtones to a fully chromatic spread.

The controls and tuning modes

The front panel keeps things compact, with a small set of knobs and buttons doing a lot of work. A long press on the Wave Button reaches the Mod page, and the Mode Button selects between four string spacing modes¹.

The four string spacing modes, selected with the Mode Button, are¹:

• Single, with harmonic overtones
• Stacked neutral thirds
• Stacked fifths
• Chromatic

Guitar Pedal X listed the same set at the unveiling as the Tuning Mode switch: Single + Overtone, Stacked Natural Thirds, Stacked Fifths, and Chromatic x12³. The single mode with overtones behaves like one string's harmonic series ringing behind your playing, while the chromatic mode spreads resonances across all twelve pitches, which the maker likens to the suspensions of a grand piano¹. Two footswitches handle the rest: an Engage Footswitch and an Aux Footswitch³.

Power

The Prismatic Wall runs on 9V DC through a 2.1mm center negative barrel jack, with a maximum current draw of 120mA¹. Electronic Audio Experiments recommends a regulated, isolated supply rated for at least 200mA minimum to accommodate startup surges, so it is worth giving it its own tap rather than sharing a daisy chain³.

MIDI, presets and the CTRL jack

For a compact pedal, the Prismatic Wall has full MIDI implementation, with CCs and presets available for all parameters, both analog and digital¹. There are 16 preset slots in total: 3 are accessible from the front panel, and the rest via MIDI¹.

The CTRL jack handles MIDI, expression, and CV input³, which opens up real-time control of parameters from an expression pedal or an external control voltage. For MIDI over this jack there is a detail worth knowing: the Prismatic Wall uses what Electronic Audio Experiments calls a "Tip Active" jack configuration, so you must use a MIDI Box, a device that converts standard DIN MIDI to TRS format⁴.

Versions, firmware and finishes

The Prismatic Wall was originally released as Version 1 during June 2024¹. At the unveiling it was available for preorder from the Electronic Audio Experiments webstore, with a handful of units remaining in the first batch at the time of writing³.

Firmware V1.1 followed on 2024-08-01, starting at serial number 326, and fixed a bug that could cause the panel to load improperly on startup¹. The product page also lists a V1.0 dated July 2024, and the two entries are not reconciled, so units before serial 326 may carry either designation depending on the record you consult¹.

The pedal has shipped in three finishes¹:

• Standard: light pink with black and white print, updated in late 2025
• Shadowfell: black texture with purple print
• Acid Etch: hand-finished using hydrochloric acid with a toner transfer mask, with application and technique varying between batches and individual units

The Acid Etch finish in particular means no two enclosures look alike, since the etching process varies from unit to unit¹. All Electronic Audio Experiments pedals come with a warranty tied to the original owner¹.

What reviewers said

Guitar Pedal X covered the Prismatic Wall twice in 2024. At the June unveiling, Stefan Karlsson and John Snyder presented it as "a really unique and innovative" sympathetic strings resonator, synthesizer and reverberator, priced at $399 in the US and £429 at Joe's Pedals in the UK³. In December, the site named it in its round-up of the year's best new modulation and utility pedals, calling it "a really unique and rare variety of Modulator"².

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