Iron Ether Arcing Prisms

The Iron Ether Arcing Prisms is an analog pedal that combines a frequency shifter with a comb filter and delay line, locked together in a feedback loop¹. The core idea is simple and unusual: the frequency shifter sits inside the feedback loop of the delay, so every time the sound repeats, it gets shifted again². Instead of a delay that fades out unchanged, each repeat drifts further away from the original note.

Iron Ether's own way of describing the effect is a visual one. The maker explains the name as a picture of what a frequency shifter does to sound¹:

A frequency shifter inside a delay's feedback loop

A frequency shifter is not a pitch shifter. A pitch shifter transposes a sound by a musical interval, keeping the harmonic relationships of the original intact. A frequency shifter moves each harmonic by a fixed amount, so the spacing between harmonics changes and the timbre itself bends and spreads out. Iron Ether compares this to a prism splitting light into a rainbow¹.

The Arcing Prisms places that shifter inside the feedback loop of a delay line, so each repeat is shifted again². The maker describes the loop as a chain of prisms: "as the sound leaves one 'prism' it enters another and gets bent again, potentially over and over depending on the amount" of feedback¹. With the Feedback knob low, the effect is a shifted echo that decays quickly. With it high, the sound can spiral, transformed on every pass through the loop.

Because the delay time and shift amount are both variable, the same circuit covers ground that players usually associate with several different delay, flanger and phaser pedals. Very short delay times with small shifts behave like flanging and phasing; longer times behave like a delay whose repeats never repeat¹⁵³.

Controls

Large hexagon and small triangle modes

The Range switch has two modes, marked with a large hexagon and a small triangle³.

• Large hexagon mode gives access to the full range of delay times, up to around one second, and the full frequency shifting range³.
• Small triangle mode limits the delay line to very short times and the shifting to only a small range around zero, keeping the effect in flanger and phaser territory³.

For a player who wants the pedal as a modulation box rather than a shifting delay, small triangle mode keeps the knobs usable across their whole travel instead of concentrating all the subtle settings at one end³.

Expression control

An expression pedal can be routed to delay time, frequency shift amount, or feedback, with an expression attenuator built in³. The Expression switch selects the target, and the Exp knob sets how much of the expression pedal's travel is added to that parameter³.

One extra use is built in: with no expression pedal connected, the Exp knob can extend the frequency shifting range higher when the Expression toggle is set to Shift³. Set it to 0 when the pedal is used without an expression pedal.

The related Super Arcing Prisms takes the same effects and adds foot-switch access to them. Iron Ether says an expression pedal on that pedal can control any of the main parameters, "sweeping from a flanger to delay, or phaser to frequency shifter," and describes results including "phasers that seem to shift forever up or down"⁵.

The engraved limited edition

The Arcing Prisms sold as an engraved and hand-painted edition, which Iron Ether describes as "a visual representation of that process," meaning the frequency shifting the pedal performs¹. The related Super Arcing Prisms carries its graphics engraved three-dimensionally into the enclosure and hand-finished in three colors⁵.

Both pedals ship in 5 business days, Monday to Friday¹⁵.

Power and size

The pedal runs on an industry-standard 9 volt DC center-negative power supply and draws 85mA³. It measures 4.7" x 2.5" (12cm x 6.3cm), about the footprint of a standard compact pedal³.

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