Envelope Follower

Track the amplitude and dynamics of a signal over time, with peak or RMS detection.

What it does

Envelope Follower tracks the level of a signal over time and outputs it as a smoothly moving value. Input can be audio, a number, or any wired value. Attack and Release set how fast the level rises and falls. The signal is also split into three bands, bass, mid and treble, around two crossover frequencies, so bass hits can drive one thing and high-end detail another.

Detection Mode sets how the level is measured. Peak follows instantaneous spikes and reads as snappy and percussive. RMS follows average power and reads as smoother, closer to perceived loudness.

When to use it

A value that pulses with a beat, a voice or any signal, driving scale, colour or opacity
A sidechain-style duck-when-loud reaction
Separate reactions to bass, mid and treble content instead of one broadband number
A fast, punchy response (lower Attack) or a slower-settling one (raise Release)

Parameter	Type	Default	What it does
`audio_in`	Number or Vec2 or Vec3 or Color or Number[] or Vec2[] or Vec3[] or Color[]	—	Signal to analyze. Accepts Number, Vec2, Vec3, Color, NumberArray, and vector/color array variants.
`mode`	String	"Peak"	Peak: track instantaneous peaks. RMS: track root-mean-square power. One of: Peak, RMS.
`attack`	Number	10	Attack time in ms - how fast the envelope rises
`release`	Number	100	Release time in ms - how fast the envelope falls
`low_crossover`	Number	200	Low/mid crossover frequency (Hz)
`high_crossover`	Number	3000	Mid/high crossover frequency (Hz)

Gotchas

envelope_db carries the same broadband level in decibels, for a wider dynamic range than the 0–1 envelope output.

Switching Mode between Peak and RMS resets the follower's internal smoothing state. The two measure the signal too differently to carry over, so expect a brief re-settle after the switch.

Changing either crossover frequency reshapes the band split and resets the per-band envelopes (bass, mid, treble). Attack and Release retune the existing smoothing and never reset, so both are safe to animate live.

Worked example

Add an Envelope Follower and wire an audio or signal source into Signal.
Leave Mode on Peak for a punchy response, or switch to RMS for a smoother one.
Lower Attack for a snappier rise, raise Release for a slower fade-out.
Wire envelope into the parameter to react: scale, opacity, colour.
For band-specific reactions, wire bass, mid or treble instead, and adjust the crossover frequencies to taste.

Envelope Follower

What it does

When to use it

Gotchas

Worked example

See also