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Shimmer Reverb

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Often followed by + Filter + Limiter + Gain

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Settings are written to the URL as you change them. Nothing differs from the defaults yet.

Add a rising reverb tail

A shimmer reverb transposes its own tail. The reverb network feeds back into itself, and on the way round the signal passes through a pitch shifter, so each repeat sits an interval above the one before it. What comes out climbs and thins as it fades, which is the sound behind most ambient guitar and pad production.

Decay sets how long the tail runs, Shimmer sets how much of it is transposed, and Interval sets by how much.

Why the shifter has to be inside the loop

Putting a pitch shifter in front of a reverb gives you one transposed signal in a room. Putting one after gives you a transposed room. Neither climbs, because the transposition happens once.

The tank here is a four line feedback delay network with a single shared feedback path, and the shifter sits in that path. A signal that has been round three times has been transposed three times. That is also why this cannot be built by chaining the reverb and pitch shifter steps in the workflow: nothing in a chain feeds its own output back into an earlier step.

A feedback delay network is used rather than the comb bank in the room reverb or the figure of eight in the plate. Those two have four and two feedback paths, which would need a pitch shifter in each, and each one would climb at its own rate.

Decay and Shimmer

Decay is the gain applied once per pass, so it sets the length of the tail. Shimmer is a blend, not an addition: it decides how much of the loop signal comes from the shifter and how much passes through untouched. Because it is a blend, raising Shimmer never raises the loop gain, and the network stays stable at any combination of the two.

  • Shimmer at 0: a plain reverb, with the shifter doing nothing.
  • 30 to 50%: the source stays recognisable and the tail lifts above it.
  • 100%: nothing untransposed returns to the loop, and the tail leaves the source entirely within a second.

Interval

An octave up is the usual setting and the one most pedals are fixed at. A fifth up stacks into a chord rather than a scale of octaves, which suits sustained chords and muddles single notes. Two octaves up thins out fast and works as a high sparkle over something else. An octave down turns the tail into a drone under the source instead of over it.

Damping and pre-delay

Damping is a filter inside the loop, so it compounds on every pass. Since each pass also moves the signal up an octave, damping is doing more work here than in a normal reverb: without it the tail gathers in the top of the spectrum and turns harsh after a few seconds.

Pre-delay holds the reverb off the front of the source. 20 to 40 ms keeps a vocal or a picked note readable ahead of its own tail.

Settings to start from

A guitar pad: Decay 75, Shimmer 50, octave up, Damping 50, Mix 40. Held synth chords: Decay 85, Shimmer 70, fifth up, Damping 35. A vocal that needs air rather than an effect: Decay 55, Shimmer 25, octave up, Mix 20.

Frequently Asked Questions

A pitch shifter inside the feedback loop. Every trip round the loop is transposed again, so the second pass sits an octave above the first and the third an octave above that. The tail rises while it fades instead of following the source down.

Position. A pitch shifter placed before or after a reverb transposes once, which gives one shifted copy decaying normally. Here the shift happens on every pass, so the interval stacks and the tail keeps climbing for as long as the decay lasts.

It sets how much of the signal going back into the loop comes from the pitch shifter rather than from the loop itself. At 0 the effect is a plain reverb. At 100 every pass is transposed, which is the most extreme setting and also the least like the source.

The shifter is granular rather than a phase vocoder, so it carries a few cents of error, and each pass shifts the output of the last one. Those errors accumulate into a cluster rather than a chord. That spreading is the sound: an exact stack of octaves reads as an organ, not as a shimmer.

After compression and before the limiter, like any reverb. Ahead of a filter if you want to keep the top of the rising tail under control, since the shimmer moves energy upward on every pass and can gather in the treble.

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