Env Filter
Headrush Wah & Filter

Env Filter

Inspired by DOD® FX25 Envelope Filter

Dynamic auto-wah type effect, controlled NOT by the pedal but by the dynamics of the signal (volume/attack).

  • The louder you play → the filter opens
  • Play softly → the filter remains closed

GENERAL FUNCTION

Filter dynamic band pass.

It reacts toenvelope of the signal.

Produces effects:

  • funk (auto-wah)
  • rhythmic groove
  • synth-like

Control Parameters

Range%
  • Range: 0 – 100%
  • Function: amount of filter movement

Behavior:

  • low (0–30%): limited movement
  • medium (40–70%): controlled effect
  • high (80–100%): full sweep

What it actually does:

  • determines how much the filter opens/closes
  • is the equivalent of the “wah excursion”

more Range = more evident effect

Sensitivity%
  • Range: 0 – 100%
  • Function: sensitivity to dynamics (input level)

Behavior:

  • low: you need to play loudly to activate it
  • medium: natural response
  • high: reacts even to weak signals

What it does:

  • controls how much the filter reacts to the volume of your playing

More Sensitivity = easier to activate the effect

Pro Tips

  • Sensitivity too high → effect always active
  • Sensitivity too low → almost absent effect
  • Range too high → may become excessive

Works best with:

  • controlled dynamics
  • precise picking

Basic trick:

  • rule Sensitivity FIRST
  • then set Range

So you get real control over the effect

Quick Reference

  • Range (%): filter movement amplitude
  • Sensitivity (%): dynamic sensitivity

Basic trick:

  • rule Sensitivity FIRST
  • then set Range

So you get real control over the effect.Range (%)

Range: 0 – 100%

Function: amount of filter movement

Behavior:

Value

Effect

low (0–30%)

limited movement

medium (40–70%)

controlled effect

high (80–100%)

full sweep

What it actually does:

determines how much the filter opens/closes

is the equivalent of the “wah excursion”

more Range = more evident effect

Sensitivity (%)

Range: 0 – 100%

Function: sensitivity to dynamics (input level)

Behavior:

Value

Effect

Bass

you need to play loudly to activate it

medium

natural response

high

reacts even to weak signals

What it does:

controls how much the filter reacts to the volume of your playing

more Sensitivity = easier to activate the effect

Setup Examples

CLASSIC FUNK PRESET (tight & groove)

Range65–75%
Sensitivity55–65%

Result:

  • quick opening of the filter
  • controlled “auto wah” effect
  • very defined groove

Ideal for:

  • clean funk rhythms
  • single coil guitar

AGGRESSIVE FUNK PRESET (slap / percussive)

Range80–90%
Sensitivity70–85%

Result:

  • very noticeable effect
  • “snap” attack
  • almost synth-like

Ideal for:

  • modern funky
  • fast rhythmic parts

PRESET FUNK SOFT (smooth / vintage)

Range40–55%
Sensitivity45–55%

Result:

  • more musical and rounded effect
  • less intrusive

Ideal for:

  • accompaniment
  • soul / disco