Effect Menu
From Audacity Manual
To apply an effect, select part or all of the tracks you want to modify, and select the effect from the menu. Titles which end in an ellipsis (...) will bring up a dialog asking you for more parameters.
Some types of effects in Audacity support real-time preview. These are: LADSPA, VST and Audio Units.
Although by default, the only effects shortcut is CTRL + R to repeat the last used effect, it is possible to set up your own shortcut for any effect in the menu. For instructions on how to do this please see Keyboard Preferences.Contents
- Built-in effects
- Nyquist effect plugins
- LADSPA effect plugins
- LV2 effect plugins
- VST effect plugins
- Audio Unit plugins (Mac only)
Built-in effects
Audacity's built-in effects (those that appear in the program irrespective of the contents of your Audacity and other "Plug-Ins" folders) are above the divider in the Effect menu.
All selected tracks are previewed irrespective of whether the tracks are muted or soloed. This is because the effect is applied to the selected audio. If Preview does not sound quite as you want, adjust the controls of the effect and Preview again.
Built-in effects do not support real-time preview.
Amplify...
Increases or decreases the volume of the audio you have selected. When you open the dialog, Audacity automatically calculates the maximum amount you could amplify the selected audio without causing clipping (distortion caused by trying to make the audio too loud).
Auto Duck...
Reduces (ducks) the volume of one or more tracks whenever the volume of a specified "control" track reaches a particular level. Typically used to make a music track softer whenever speech in a commentary track is heard.
Bass and Treble...
Increases or decreases the lower frequencies and higher frequencies of your audio independently. It behaves just like the bass and treble controls on a domestic stereo system.
Change Pitch...
Change the pitch of a track without changing its tempo.
Change Speed...
Change the speed of a track, also changing its pitch.
Change Tempo...
Change the tempo of a selection without changing its pitch.
Click Removal...
Click Removal is designed to remove clicks on audio tracks and is especially suited to declicking recordings made from vinyl records. It will usually work best on very short clicks. For broader individual pops in selections up to 128 samples wide (about three milliseconds at 44100 Hz project rate), you could try the Repair effect.
Compressor...
Compresses the dynamic range by two alternative methods. The default "RMS" method makes the louder parts softer, but leaves the quieter audio alone. The alternative "peaks" method makes the entire audio louder, but amplifies the louder parts less than the quieter parts. Make-up gain can be applied to either method, making the result as loud as possible without clipping, but not changing the dynamic range further.
Echo...
Repeats the selected audio again and again, normally softer each time. The delay time between each repeat is fixed, with no pause in between each repeat. For a more configurable echo effect with a variable delay time and pitch-changed echoes, see Delay...
Equalization...
Adjusts the volume levels of particular frequencies.
Fade In
Applies a fade-in to the selected audio, so that the amplitude changes gradually from silence at the start of the selection to the original amplitude at the end of the selection. The shape of the fade is linear. The rapidity of the fade-in depends entirely on the length of the selection it is applied to.
Fade Out
Applies a fade-out to the selected audio, so that the amplitude changes gradually from the original amplitude at the start of the selection down to silence at the end of the selection. The shape of the fade is linear. The rapidity of the fade-out depends entirely on the length of the selection it is applied to.
Invert
Flips the audio samples upside-down. This normally does not affect the sound of the audio at all. It is occasionally useful for vocal removal.
Leveler...
Leveler is a simple, combined compressor and limiter effect for reducing the dynamic range of audio. It reduces the difference between loud and soft, making the audio easier to hear in noisy environments or on small loudspeakers. It is best suited to speech recordings but at heavier settings or used multiple times it can also be used as a simple distortion effect for voices or instruments.
Noise Reduction...
Reduces constant background noise such as fans, tape noise, or hums. It will not work for removing talking or music in the background.
Normalize...
Use the Normalize effect to set the maximum amplitude of a track, equalize the amplitudes of the left and right channels of a stereo track and optionally remove any DC Offset from the track.
Nyquist Prompt...
Launches a dialog where you can enter Nyquist commands. Nyquist is a programming language for producing and processing audio. For more information see Nyquist Plugins Reference.
Paulstretch...
Use Paulstretch only for an extreme time-stretch or "stasis" effect. This may be useful for synthesizer pad sounds, identifying performance glitches or just creating interesting aural textures. Use Change Tempo or Sliding Time Scale rather than Paulstretch for tasks like slowing down a song to a "practice" tempo.
Phaser...
The name "Phaser" comes from "Phase Shifter", because it works by combining phase-shifted signals with the original signal. The movement of the phase-shifted signals is controlled using a Low Frequency Oscillator (LFO).
Repair
Fix one particular short click, pop or other glitch no more than 128 samples long.
Repeat...
Repeats the selection the specified number of times.
Reverb...
Adds ambience or a "hall effect".
Reverse
Reverses the selected audio, so that it will sound as if it is playing from the end to the start.
Sliding Time Scale / Pitch Shift...
Allows you to make a continuous change to the tempo and/or pitch of a selection by choosing initial and/or final change values.
Time Tracks can be used to bend tempo more flexibly (also affecting pitch) using Envelope Tool.
Truncate Silence...
Automatically try to find and eliminate audible silences. Don't use with faded audio.
Wahwah...
Rapid tone quality variations, like that guitar sound so popular in the 1970's.
Wahwah uses a moving bandpass filter to create its sound. A low frequency oscillator (LFO) is used to control the movement of the filter throughout the frequency spectrum.
The phase of the left and right channels is automatically adjusted when given a stereo track, so that the effect seems to travel across the speakers.
Nyquist effects
Nyquist effects do not support real-time preview, import/export of presets or saving presets for use in Audacity.
Nyquist plugins provide most of the optional effects underneath the divider in the Effect menu. They are also used to provide some of Audacity's built-in audio generators and analysis tools. A wide range of additional Nyquist effect, generation and analysis plugins can be obtained from Download Nyquist Plugins on our Wiki.
- On Windows and OS X the "Plug-Ins" folder is in the directory where Audacity resides - usually C:\Program Files or C:\Program Files (x86) on Windows or the "Applications" folder on OS X.
- On Linux, the "plug-ins" folder is in usr/share/audacity if you installed an Audacity package supplied by your distribution, or usr/local/share/audacity if you compiled Audacity from source code. Optionally a "plug-in" folder can be created in the home directory ~/.audacity-files/plug-ins.
Nyquist Workbench
For advanced users who can compile Audacity, Nyquist Workbench gives the ability to run arbitrary Nyquist code in Audacity from a graphical IDE (Integrated Development Environment). See Nyquist Workbench in the Wiki for details.
Nyquist plugins included in Audacity
The following sample Nyquist plugins are included in released builds of Audacity:
Adjustable Fade...
Launches a dialog box where you can choose the shape of the fade in or fade out to be applied. You can also create fades to and from other than silence or full volume. An example of this might be a fade in from 20% of the original volume to 80% of the original volume.
Clip Fix...
Attempts to reconstruct clipped regions by interpolating the lost signal.
Crossfade Tracks
Applies a crossfade to a selected region of a pair of tracks.
Delay...
A configurable delay effect with variable delay time and pitch shifting of the delays.
High Pass Filter...
Passes frequencies above its cutoff frequency and attenuates frequencies below its cutoff frequency; this can be used to reduce low frequency noise.
Low Pass Filter...
Passes frequencies below its cutoff frequency and attenuates frequencies above its cutoff frequency; this can be used to reduce high pitched noise.
Notch Filter...
Greatly attenuate ("notch out") a narrow frequency band. This is a good way to reduce mains hum or a whistle confined to a specific frequency with minimal damage to the remainder of the audio.
Spectral edit multi tool
If a fully defined spectral selection has been made, choosing Spectral edit multi-tool applies the appropriate filter for the selection. See Spectral edit multi tool for more information.
Spectral edit parametric EQ...
If a fully defined spectral selection has been made, the effect applies a band cut or band boost according to the value you enter in the "Gain (dB)" control. See Spectral edit parametric EQ for more information.
Spectral edit shelves...
If a fully defined spectral selection has been made, the effect applies a low shelf filter, high shelf filter or combined low and high shelf filter according to the value you enter in the "Gain (dB)" control. See Spectral edit shelves for more information.
Studio Fade Out
Produces a smooth and musical sounding fade out, by applying a sinusoidal fade with a progressive low pass filter from full spectrum at the start of the selection to 100 Hz at the end.
Tremolo...
Modulates the volume of the selection at the depth and rate selected in the dialog. The same as the tremolo effect familiar to guitar and keyboard players.
Vocal Remover (for center-panned vocals)...
Attempts to remove center-panned audio from a stereo track; vocals are often (but not always) recorded in this way. Vocals (or other audio) can only be removed with this plugin when panned to center, in other words sounding equally loud in both left and right channels. Help text is available from within the effect's dialog box.
Vocoder...
Vocoder synthesizes a modulator (usually a voice) in the left channel of a stereo track with a carrier wave in the right channel to produce a modified version of the left channel. Vocoding a normal voice with white noise as provided in the effect will produce a robot-like voice for special effects. Other carriers can be used for subtly different voices. Vocoder can only be applied to unsplit stereo tracks.
LADSPA effects
LADSPA (Linux Audio Developer's Simple Plugin API) plugins were originally developed for the Linux platform, but ports of some plugins are available for Windows and OS X as well. Most LADSPA plugins are effects, but they are also used to provide some of Audacity's built-in audio generators and can be used for audio analysis. Additional LADSPA plugins can be downloaded for Windows, Mac and Linux.
LADSPA effects support real-time preview. They do not support import/export of presets but do support saving presets for use in Audacity only. A few LADSPA plugins have an "Effect Output" section which is populated after the effect is applied.
Loading of LADSPA effects is controlled by the Register Effects dialog.
LADSPA plugins shipped with Audacity
Two sample LADSPA effects are included with Windows and Mac builds of Audacity:
Hard Limiter...
An extreme compressor effect. It can sometimes be used to remove stubborn clicks.
SC4...
A stereo compressor with a variable envelope follower for RMS / peak behaviour.
Adding a LADSPA plugin
To add a LADSPA plugin, put it in the Audacity "Plug-ins" folder:
- On Windows and OS X the "Plug-ins" folder is in the directory where Audacity resides - usually C:\Program Files or C:\Program Files (x86) on Windows or the "Applications" folder on OS X.
- On Linux, the "plug-ins" folder is in usr/share/audacity if you installed an Audacity package supplied by your distribution, or usr/local/share/audacity if you compiled Audacity from source code. Optionally a plugins folder can be created in the home directory ~/.audacity-files/plug-ins.
Go to Effects Preferences and make sure that is selected, then click . The next time you launch Audacity, the Register Effects dialog will appear, listing the newly-added plugins. Put a checkmark in the box for each plugin you want to enable.
- All operating systems: The path specified by the LADSPA_PATH environment variable
- additionally on OS X:
- ~/Library/Audio/Plug-Ins/LADSPA
- /Library/Audio/Plug-Ins/LADSPA
- additionally on Linux/Unix:
- ~/.ladspa
- /usr/local/lib/ladspa
- /usr/lib/ladspa
- $LIBDIR/ladspa
Saving LADPSA effect settings as a User Preset
To save the current effect settings as a User Preset, select Save As... from the Manage menu in the effect dialog which brings up the following dialog:
Type a name for the preset then click
after which the saved preset will appear in the "User Presets" list in the Manage menu.LADSPA Effect Options
In the effect's dialog, click the Manage button then choose to bring up the dialog illustrated below. When you change the options in this dialog, the changes apply only to the current effect that's open. All other LADSPA effects will remain at the default options shown below until you change their options.
- Latency Compensation: This setting (enabled by default) compensates for waveform delay caused by LADSPA effects which preload audio data to a buffer. Compensation may not work in all cases, and for it to work, any compensation or latency reporting settings in the effect itself must be enabled. If compensation fails or if this Audacity setting is unchecked, effects that buffer audio will insert silence at the start of the processed selection and remove a corresponding amount of audio from the end of the selection. Enabling or disabling compensation is effective immediately.
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Effects of the following LV2, VST and Audio Unit (Mac only) classes are always third-party plugins added by the user (and also by the operating system in case of Audio Units). |
LV2 effects
LV2 effects do not support real-time preview, import/export of presets or saving presets for use in Audacity.
LV2 effects do not yet support graphical interface, so are textual interface only.
Some LV2 effects require features that are not yet supported in Audacity, so error when applying the effect.
LV2 is a more advanced evolution of the LADSPA plugin architecture. Note that LV2 effects in Audacity cannot yet display a full graphical interface. Each time you launch Audacity it scans for and loads all detected LV2 effects.
To add a new LV2 effect, place its complete ".lv2" folder (not the files alone) at the top level of any of the following searched for locations, then restart Audacity.
- Windows
- Users\<user name>\AppData\Roaming\LV2 (or Documents and Settings\<user name>\Application Data\LV2 on Windows XP)
- Program Files\Common Files\LV2 (or Program Files (x86)\Common Files\LV2 on 64-bit systems)
- Mac:
- ~/.lv2
- ~/Library/Audio/Plug-Ins/LV2
- /Library/Audio/Plug-Ins/LV2
- /usr/local/lib/lv2
- /usr/lib/lv2
- Linux:
- ~/.lv2
- /usr/local/lib/lv2 or /usr/local/lib64/lv2
- /usr/lib/lv2 or /usr/lib64/lv2
- Windows:
- %APPDATA%\LV2;%COMMONPROGRAMFILES%\LV2;%COMMONPROGRAMFILES(x86)%\LV2
- Mac OS X:
- $HOME/.lv2:$HOME/Library/Audio/Plug-Ins/LV2:/Library/Audio/Plug-Ins/LV2:/usr/local/lib/lv2:/usr/lib/lv2
- Linux:
- $HOME/.lv2:/usr/local/lib/lv2:/usr/lib/lv2 (assuming $PREFIX is /usr/local as it should be by default)
VST effects
VST effects support real-time preview.
VST effects support import/export of presets (where the particular effect supports this) and support saving presets for use in Audacity only.
Loading of VST effects is controlled by the Register Effects dialog.
Adding a new VST effect in Audacity
A wide range of VST effects can be obtained online. To add a new VST effect most easily, put its DLL (Windows), VST (Mac) or SO (Linux) file plus any configuration files or folders it requires in the Audacity "Plug-ins" or "plug-ins" folder inside the directory where Audacity resides.
Then:
- Go to the Effects tab of Preferences
- Under "Plugin Options", ensure that the checkbox has a checkmark, then click (this checkbox should be enabled by default, so this step is usually not required).
- Restart Audacity then in the Register Effects dialog, verify your newly added VST plugins have a checkmark and click . Any newly added LADSPA or Audio Unit effects (Mac OS X) which you checkmark in the dialog will also be loaded.
Here is a complete list of locations where Audacity searches for VST effects.
- Windows, Mac and GNU/Linux:
- The Audacity plug-ins folder in the location Audacity is run from:
- On Windows and OS X the "Plug-Ins" folder is in the directory where Audacity resides - usually C:\Program Files or C:\Program Files (x86) on Windows or the "/Applications" folder on OS X
- On Linux you must add a "plug-ins" folder to /usr/bin/ (if you installed a packaged version of Audacity) or to /usr/local/bin (if you installed a self-compiled version of Audacity)
- The "Plug-Ins" folder in Audacity's folder for application data.
- The Audacity plug-ins folder in the location Audacity is run from:
- Also on Windows:
- C:\Program Files\Steinberg\VSTPlugins (or C:\Program Files (x86)\Steinberg\VSTPlugins on 64-bit systems).
- Windows Registry key HKCU\Software\VST\VSTPluginsPath
- Windows Registry key HKLM\Software\VST\VSTPluginsPath
- All paths specified by the "VST_PATH" environment variable.
- Also on Mac OS X:
- ~/Library/Audio/Plug-Ins/VST
- /Library/Audio/Plug-Ins/VST
- All paths specified by the "VST_PATH" environment variable.
- Also on GNU/Linux:
- All paths listed in the "VST_PATH" environment variable
- If no VST_PATH environment variable is found, the following are searched:
- LIBDIR/vst (where LIBDIR is defined at build time)
- /usr/lib/vst
- /usr/local/lib/vst
- ~/.vst.
Saving, Exporting and Importing VST Effect Presets
Save As...
To save the current effect settings as a User Preset, select Save As... from the Manage menu in the effect dialog which brings up the following dialog:
Type a name for the preset then click
after which the saved preset will appear in the "User Presets" list in the Manage menu.Export...
Presets for VST effects are exported to a file. A presets file lets you move settings for a particular effect between computers on any operating platform that supports that effect.
Select Export... from the Manage menu in the effect dialog to bring up the "Save VST Preset As:" dialog
Be sure to choose a file type in the “Save as type:” dropdown menu (“Format” dropdown menu on Mac)
Type a name for the file in the "File Name" box ("Save As:" box on Mac) then click
to export the current effect settings to a separate file.The following file formats are supported:
- XML format: The default choice, which saves an Audacity VST preset file. This is the least flexible choice, mainly useful for the small number of effects that don't support FXP presets. Most other VST host applications don't support XML, so you may only be able to share XML presets between other computers running Audacity.
- FXP format: Saves a standard VST program file, which is the most portable choice. It allows you to save the currently visible settings. The saved preset can then be loaded by the same effect running in Audacity or most other VST host applications, on any computer or operating platform it supports. Similarly FXP presets saved by a given effect in any VST host on any computer can be loaded into that effect in Audacity.
- FXB format: Saves a standard VST bank file, containing the current settings of all the factory presets for the effect. The saved "bank" of factory presets at your favorite settings can then be loaded by the same effect running in Audacity or any other VST host application supporting FXB presets, on any computer or operating platform it supports. Similarly an FXB bank saved by a given effect in any VST host on any computer can be loaded into that effect in Audacity.
By default presets are saved to the same location as the audacity.cfg file, but you can choose to save them anywhere. Since there is no distinction between preset files saved by different effects you may want to create a folder for each effect you save presets for, or include the effect name in the file name.
Import...
Select Import... from the Manage menu in the effect dialog to bring up the "Load VST Preset:" dialog
Navigate to the place where you exported a VST preset file.
Click the open button to load the settings.
Depending on how the particular VST effect handles importing presets, the imported preset may show up in the User Presets submenu, the Factory Presets submenu or may not show up at all.
VST Effect Options
In the effect's dialog, click the Manage button then choose to bring up the dialog illustrated below. When you change the options in this dialog, the changes apply only to the current effect that's open. All other VST effects will remain at the default options shown below until you change their options.
- Buffer Size: Controls the number of samples sent to the effect in each round of processing. The default buffer size of 8192 should be safe for all VST effects. You can set a higher value which will allow faster processing but some effects may not work at higher values. Changing the buffer size is effective immediately.
- Latency Compensation: This setting (enabled by default) compensates for waveform delay caused by VST effects which preload audio data to a buffer. Compensation may not work in all cases, and for it to work, any compensation or latency reporting settings in the effect itself must be enabled. If compensation fails or if this Audacity setting is unchecked, effects that buffer audio will insert silence at the start of the processed selection and remove a corresponding amount of audio from the end of the selection. Therefore leave this option checked unless a particular VST does not work even after reducing the buffer size, in which case you can experiment by unchecking this option. Enabling or disabling compensation is effective immediately.
- Graphical Mode: This setting (enabled by default) allows most VST effects to display a graphical (instead of a plain text) interface. If you change this setting you must close the settings dialog, then close and reopen the effect to see the change. This option is the same as the Display VST Effects in Graphical Mode option in Effects Preferences.
Audio Unit effects
Audio Units (AU) are a system-level plugin architecture provided on Mac OS X computers.
Audio Unit effects support real-time preview.
Audio Unit effects support import/export of presets (see the description below of how it works) and support saving presets for use in Audacity only.
Loading of Audio Unit effects is controlled by the Register Effects dialog.
Adding Audio Unit effects
To add a new Audio Unit effect, place it in either of the following system plugin directories:
- ~/Library/Audio/Plug-Ins/Components (user plugins)
- /Library/Audio/Plug-Ins/Components (system-wide plugins)
then go to Effects Preferences and make sure that is selected, then click . The next time you launch Audacity, the Register Effects dialog will appear, listing the newly-added plugins. Put a checkmark in the box for each plugin you want to enable.
Saving, Exporting and Importing Audio Unit Effect Presets
Save As...
To save the current effect settings as a User Preset, select Save As... from the Manage menu in the effect dialog which brings up the following dialog:
Type a name for the preset then click
after which the saved preset will appear in the "User Presets" list in the Manage menu.Export...
Before you can export a preset you must already have saved it as a User Preset.
Each preset for Audio Unit effects is exported to a separate ".aupreset " file at /Users/<yourUserName>/Library/Audio/Presets/Apple/<effectName>/. A presets file lets you move settings for a particular effect between computers.
To export a saved User Preset, open the Manage menu
, choose "User Presets" then select the saved preset to load it into the effect, then choose from the Manage menu to bring up the following dialog:
Select the user preset you want to export then click
to export it to a file. If there is only one preset in the list you must still select it, or nothing will be exported.Import...
Select Import... from the Manage menu in the effect dialog to bring up the following dialog:
Select the presets you want to import then click
to import each preset file as a User Preset.To be sure the imported preset you want to use is loaded into the effect, select it from "User Presets".
Audio Unit Effect Options
In the effect's dialog, click the Manage button then choose to bring up the dialog illustrated below. When you change the options in this dialog, the changes apply only to the current effect that's open. All other Audio Unit effects will remain at the default options shown below until you change their options.
- Latency Compensation: This setting (enabled by default) compensates for waveform delay caused by Audio Unit effects which preload audio data to a buffer. Compensation may not work in all cases, and for it to work, any compensation or latency reporting settings in the effect itself must be enabled. If compensation fails or if this Audacity setting is unchecked, effects that buffer audio will insert silence at the start of the processed selection and remove a corresponding amount of audio from the end of the selection. Enabling or disabling compensation is effective immediately.
- Graphical Mode: This setting (enabled by default) allows most Audio Unit effects to display a graphical (instead of a plain text) interface. If you change this setting you must close the settings dialog, then close and reopen the effect to see the change.