From Audacity Development Manual
Jump to: navigation, search

Rapid tone quality variations, like that guitar sound so popular in the 1970's.
Accessed by: Effect > Wahwah...

This effect uses a moving band-pass filter to create its sound. A low frequency oscillator (LFO) is used to move the pass-band back and forth in the frequency spectrum. Resonances accentuate tones near that center of the band, and as that center frequency varies the accentuated frequencies vary too.
Advice The output from this effect may have higher amplitude than the original audio. If the output exceeds 0 dB (full track height) and so triggers the red clipping warning lights in the Playback Meter, you should open Effect > Amplify..., ensure "Amplification (dB)" shows a negative dB value (not "0.0 dB") then click OK.

If "Amplification (dB)" in Amplify shows "0.0 dB", the track does not contain 32-bit audio and the clipping cannot be repaired. In that case, Edit > Undo Wahwah, use Amplify to reduce the track to a lower amplitude then reapply Wahwah.

LFO Frequency

Sets the speed at which the band-pass filter is swept back and forth.

LFO Start Phase

The start position of the LFO cycle. This determines whether the band-pass filter starts at its lowest, mid or highest frequencies. Another way to look at it is that it determines whether at the start of the effect the pitch is rising or falling.


Determines the range of frequencies that are swept through by the band-pass filter. Higher values will sweep the filter to higher frequencies and so give more variation to the sound quality over a complete LFO cycle. Lower values will give a more constant sound effect.


Determines the degree of resonance in the band-pass filter. Higher values give a more "peaky" effect.

Wah Frequency Offset

Determines the "base" frequency of the band-pass filter. Higher values will shift the filter's frequency range upwards. To achieve a Wah effect that is in the low frequencies the frequency offset needs to be set to a low value.

Output gain (dB)

Controls the amount of gain (volume) positive or negative that will be applied by the effect.

Real-time preview

This effect supports Real-time preview - effect settings can be changed while playing and listening to the result in real-time. Text-based button controls are provided as in the image above. The Enable checkbox acts like a live "Bypass" control. Uncheck the checkbox unchecked checkbox Enable to hear the audio without the effect applied, and recheck the box checked checkbox Enable to hear the effect applied at its current settings.

The Manage button accesses choices to add, delete, import or export presets for this effect and to set options for this effect. For details see Manage presets.


Clicking on the command buttons give the following results:

  • Manage gives a dropdown menu enabling you to manage presets for the tool and to see some detail about the tool. For details see Manage presets
  • Start Playback starts playback of the effect preview
  • Skip Backward skips backward through the effect preview
  • Skip Forward skips forward through the effect preview
  • checked checkbox Enable listen to the preview with or without the effect applied
  • Apply applies the effect to the selected audio with the current effect settings
  • Close closes the dialog
  • Help Button brings you to the appropriate page in the Manual, this page
The Apply button ignores the setting for Enable and applies the effect to the selected audio regardless of the Enable setting.


|< Index of Effects, Generators and Analyzers

|< Effect Menu