From Audacity Development Manual

Jump to: navigation, search

FrenchFlagSmall.png Wahwah

Rapid tone quality variations, like that guitar sound so popular in the 1970's.
Accessed by: Effect > Wahwah...
This effect uses a moving bandpass 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.
Warning icon 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 bandpass filter is swept back and forth.

LFO Start Phase

The start position of the LFO cycle. This determines whether the bandpass 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 bandpass 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 bandpass filter. Higher values give a more "peaky" effect.

Wah Frequency Offset

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

The buttons

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.
  • Preview plays a short preview of what the audio would sound like if the effect is applied with the current settings, without making actual changes to the audio. The length of preview is determined by your setting in Edit > Preferences > Playback, the default setting is 6 seconds.
  • OK applies the effect to the selected audio with the current effect settings.
  • Cancel aborts the effect and leaves the audio unchanged.


|< Index of Effects, Generators and Analyzers

|< Effect Menu

Personal tools