Envelope Follower

Tracks the amplitude envelope of an incoming audio signal and converts it into a smooth control value for driving modulation. Attack and release smoothing set how quickly the follower rises to transients and falls back on decays, and the detected level is remapped to a usable range so it can modulate filter cutoff, gain, pan, or any other target. Typical uses include auto-wah, ducking, and audio-reactive control.

Inputs

Audio In

• ID: audio
• Kind: audio
• Rate: audio
• Audio Channel Layout: stereo
• Unit: normalized
• Range: -1 to 1 normalized
• Coercion: Implicit
• Description: Audio signal input
• Default: 0

Outputs

Value

• ID: value
• Kind: control
• Rate: control
• Unit: normalized
• Coercion: Implicit
• Description: Envelope follower output remapped between Out Min and Out Max.

Parameters

Input Level

• ID: inputLevelDb
• Type: float
• Control: slider
• Range or Options: -24 to 24 dB, step 0.1
• Default: 0
• Group: Input
• Description: Pre-gain applied to the incoming signal before envelope detection.

Threshold

• ID: thresholdDb
• Type: float
• Control: slider
• Range or Options: -60 to 0 dB, step 0.1
• Default: -60
• Group: Input
• Description: Gate threshold for the detector. Higher values require a louder input to open.

Attack

• ID: attackMs
• Type: float
• Control: slider
• Range or Options: 0.1 to 1000 ms, step 0.1, log
• Default: 10
• Group: Envelope
• Description: How quickly the follower rises when the input level increases.

Release

• ID: releaseMs
• Type: float
• Control: slider
• Range or Options: 1 to 3000 ms, step 1, log
• Default: 120
• Group: Envelope
• Description: How quickly the follower falls when the input level decreases.

Out Min

• ID: outMin
• Type: float
• Control: slider
• Range or Options: -1 to 1 normalized, step 0.01
• Default: 0
• Group: Range
• Description: Minimum remapped output value.

Out Max

• ID: outMax
• Type: float
• Control: slider
• Range or Options: -1 to 1 normalized, step 0.01
• Default: 1
• Group: Range
• Description: Maximum remapped output value.

Notes

• Canonical ID: an.envelopeFollower
• Category: analysis
• Runtime Surface: audio
• Runtime Targets: audio-worklet
• JUCE Early Access: Supported
• Early Access Note: Native-supported in the plugin for the current catalog/runtime support contract.