Struct EnvelopeFollower 

pub struct EnvelopeFollower { /* private fields */ }

Envelope follower for dynamics-based modulation.

Tracks the amplitude envelope of an audio signal, producing a control signal for auto-wah, compressor side-chains, or dynamic modulation. Uses asymmetric attack/release smoothing for natural response.

Implementations

impl EnvelopeFollower

pub fn new(sample_rate: f64) -> EnvelopeFollower

Create a new envelope follower with default parameters.

Default: 10ms attack, 100ms release, unity sensitivity.

pub fn from_rc( attack_r: f64, attack_c: f64, release_r: f64, release_c: f64, sensitivity_r: f64, sample_rate: f64, ) -> EnvelopeFollower

Create an envelope follower from physical RC timing components.

This mirrors real envelope detector circuits where attack and release time constants are set by RC networks, and sensitivity is set by an input gain resistor.

• attack_r: Attack timing resistor (Ω)
• attack_c: Attack timing capacitor (F)
• release_r: Release timing resistor (Ω)
• release_c: Release timing capacitor (F)
• sensitivity_r: Sensitivity resistor (Ω) — gain = sensitivity_r / 10kΩ

Time constants: τ_attack = R_attack × C_attack (in seconds), τ_release = R_release × C_release (in seconds).

pub fn set_attack(&mut self, ms: f64)

Set attack time in milliseconds.

Shorter attack responds faster to transients but may track individual waveform cycles. Typical range: 1-50ms.

pub fn attack(&self) -> f64

Get current attack time in milliseconds.

pub fn set_release(&mut self, ms: f64)

Set release time in milliseconds.

Longer release gives smoother output but slower response to level drops. Typical range: 50-500ms.

pub fn release(&self) -> f64

Get current release time in milliseconds.

pub fn set_sensitivity(&mut self, sens: f64)

Set input sensitivity/gain.

Higher sensitivity amplifies the input before envelope detection, useful for low-level signals. Typical range: 0.5-5.0.

pub fn sensitivity(&self) -> f64

Get current sensitivity.

pub fn process(&mut self, input: f64) -> f64

Process one audio sample and return the envelope value.

The envelope tracks the rectified (absolute value) input with asymmetric attack/release smoothing. Output range is 0.0 upward, typically staying below 1.0 for normalized audio input.

pub fn envelope(&self) -> f64

Get current envelope value without processing new input.

pub fn reset(&mut self)

Reset envelope to zero.

pub fn set_sample_rate(&mut self, sample_rate: f64)

Update sample rate and recalculate coefficients.

Trait Implementations

impl Clone for EnvelopeFollower

fn clone(&self) -> EnvelopeFollower

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for EnvelopeFollower

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.