How It Works
Technical view
The current implementation matches Auto Wah exactly: a smoothed absolute-value detector drives the center frequency of a resonant low-pass filter, then a post-filter high shelf shapes the result. It already reacts to input level, but it is not yet differentiated into a separate envelope-filter voicing.
- Filter, Wah & Envelope
- resonant low-pass
- waveshaping / saturation
- delay processing
- oscillator / LFO modulation
- DC blocking
Signal Path
Compiled preview chain
Preview source: An internally generated picked-string phrase is widened to stereo with a 19-sample right-channel delay and slight left/right shelf-EQ offsets before it hits the filter core.
- 1internal picked-string demo phrase
- 2stereo spread with a short right-channel delay
- 3envelope-following resonant low-pass sweep
- 4post-filter high-shelf tone shaping
- 5dry / wet mix
- 6DC blocker
- 7output gain trim
- 8final tanh limiter
Preview source
An internally generated picked-string phrase is widened to stereo with a 19-sample right-channel delay and slight left/right shelf-EQ offsets before it hits the filter core.
Effect core
Envelope-following resonant low-pass filter with post-filter high-shelf tone shaping.
Signal path
The static waveform and the live player both reflect this compiled signal chain.
- internal picked-string demo phrase
- stereo spread with a short right-channel delay
- envelope-following resonant low-pass sweep
- post-filter high-shelf tone shaping
- dry / wet mix
- DC blocker
- output gain trim
- final tanh limiter
Controls that matter
These are the currently active controls detected in the FAUST source for this effect.
- mix: Blends the untouched stereo preview source with the filtered path after the effect core.
- output_gain_db: Applies final post-effect level trim after DC blocking and before the output limiter.
- focus: Sets the base center of the resonant low-pass filter and the post-filter high shelf.
- motion: Scales the envelope-driven sweep depth and the filter resonance.
- rate: Declared in the shared control set but unused in the current preview code.
Code-backed analysis
The generated description is tied to the active helper blocks and routing found in the current DSP.
- demo
- fx
- outputStage
- leftDemo
- rightDemo
- filterCore
- phraseMono
- previewShiftSamples
Controls
Audible controls in this DSP
Blends the untouched stereo preview source with the filtered path after the effect core.
Lower settings preserve more dry attack and full-band tone; higher settings emphasize the filter treatment.
Applies final post-effect level trim after DC blocking and before the output limiter.
Matches loudness without changing the filter behavior itself.
Sets the base center of the resonant low-pass filter and the post-filter high shelf.
Moves the filter lower or higher and changes how open the result sounds.
Scales the envelope-driven sweep depth and the filter resonance.
Makes the response more reactive and more pronounced with stronger sweeps on louder notes.
Declared in the shared control set but unused in the current preview code.
Changing it currently has no effect on the sound.
Analysis
Code-derived notes
Current implementation shares the same envelope-following resonant low-pass core as Auto Wah and Touch Wah, and the shared rate control is inactive.
Active blocks
- demo
- fx
- outputStage
- leftDemo
- rightDemo
- filterCore
- phraseMono
- previewShiftSamples
- env
- pickedVoice
- fund
- pickEnv
- ampEnv
- triggerAt
- maxDelaySamples
Inactive helpers
- synthVoice
- organVoice
- bellVoice
- softsat
- quantize
- combLP
- echoOnly
- diffuser
Warnings
No current warnings are attached to this effect.
Source
- library/filter-wah-envelope/envelope-filter.dsp
- Output stage: DC blocker -> output gain trim -> final tanh limiter
- Library position: 64