# Index of Effects, Generators, Analyzers and Tools

From Audacity Development Manual
This page is an index to the Effects, Generators, Analyzers and Tools shipped with Audacity. You may also add new plugins in various popular formats.

- Effects change the audio in some way.
  - Some effects can make the peak levels of waveforms substantially higher.
- Generators create new audio, either in an existing track or in a new track.
- Analyzers perform analysis on a selection of audio - they do not change the audio and do not create new audio.
- Tools provide miscellaneous commands that act on the project, but do not fit into the categories Effects, Generators or Analyzers.
- Plugin Manager manage your list of available built-in Effects, Generators, Analyzers and plugins.

Although by default, no keyboard shortcuts are provided for most Effect, Generate or Analyze commands, it is possible to set up your own shortcut for any of these commands. For instructions on how to do this please see Keyboard Preferences.

See this page for tips on Navigating Effects without using a mouse.

| Realtime effects: some external plugin effects can now be manipulated in real-time on any track using the effects stack. Please see Using realtime effects on the Audacity Support site.

| Note carefully that when you apply an Effect or Generator to a time-stretched clip the changed speed of the clip will be automatically rendered. If you apply an Effect or Generator to a selection within a time-stretched clip then Audacity will split the original clip so that the selection can be rendered as part of applying the effect. Analyzers are not affected by this.

| When playing, recording or paused, the Effect menu will appear grayed out, because changes to the audio data cannot be made until you press the Stop button .

| The Macros Palette, accessed by Tools > Apply Macros > Palette is a good way of having a set of favorite presets for the effects you regularly use.

## Alphabetical Index of Effects, Generators, Analyzers and Tools

Where an effect, generator or analyzer has settings, its description page (accessed by the links below) shows an image of the interface and its default settings.

Adjustable Fade | Crossfade Clips | Label Sounds | Plot Spectrum | Spectral Delete
Amplify | Crossfade Tracks | Limiter | Pluck | Spectral edit multi tool
Auto Duck | Delay | Loudness Normalization | Regular Interval Labels | Spectral edit parametric EQ
Bass and Treble | Distortion | Low-Pass Filter | Repair | Spectral edit shelves
Beat Finder | DTMF Tones | Measure RMS | Repeat | Tone
Change Pitch | Echo | Noise Gate | Reverb | Tremolo
Change Speed and Pitch | Fade In | Noise Reduction | Reverse | Truncate Silence
Change Tempo | Fade Out | Noise | Rhythm Track | Vocoder
Chirp | Studio Fade Out | Normalize | Risset Drum | Wahwah
Classic Filters | Find Clipping | Notch Filter | Sample Data Export
Click Removal | Filter Curve EQ | Nyquist Plug-in Installer | Sample Data Import |
Clip Fix | Graphic EQ | Nyquist Prompt | Shelf Filter |
Compressor | High-Pass Filter | Paulstretch | Silence |
Contrast | Invert | Phaser | Sliding Stretch |

From version 3.5.0 of Audacity Vocal Reduction and Isolation is no longer shipped with Audacity.

- The new OpenVINO AI plugins yield a better result.
- Vocal Reduction and Isolation is still available as a downloadable Nyquist plugin from the Muse Support site.
- Documentation for it is retained in the Manual here.

## Plugin Manager

Selecting this option from the Effect Menu (or the Generate Menu, Analyze Menu or Tools Menu) takes you to a dialog where you can enable or disable particular Effects, Generators and Analyzers in Audacity. Even if you do not add any third-party plugins, you can use this to make the Effect menu shorter or longer as required. For details see Plugin Manager.

By default all the built-in effects are enabled in Audacity.

Additional plugins can also be loaded into Audacity:

- See Installing plugins on the Audacity Support site for plugin installation details for all three platforms.
- See also this set of downloadable Nyquist plugins

## Buttons in the dialogs

Depending on the Effect, Generator or Analyzer you will seem some of the following button at the top of its dialog:

- Presets and settings 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.
- Apply applies the effect or analyzer to the selected audio with the current effect settings and closes the dialog.
- Generate applies the generator to the selected audio or current cursor position with the current effect settings and closes the dialog.

You may see a Debug button, please ignore that, it is there for developers to test the tool.

## Plugin Manager

## Backup or transfer your settings

To backup your settings for Effects, Generators and Analyzers, or to move your settings to another computer, you just need to access the audacity settings folder:

- Windows: C:\Users\<your username>\Appdata\Roaming\audacity
- Mac: ~/Library/Application Support/audacity
- Linux: /home/<your username>/audacity-data

| See this FAQ for details of how to access this folder on the three platforms.

In that folder you will find a file called pluginsettings.cfg. This is the file that contains the settings for your effects generators and analyzers, your last-used settings and any user presets you have saved using the "Manage" button in each effect's dialog.

- To backup your settings just copy this file to a safe location.
- You can copy this file to the same location on a different computer to transfer the settings.

## Effects by Function

See the Effect Menu for further details.

### Volume and Compression

These make the sound louder or quieter:

- Amplify: Increases or decreases the volume of the audio you have selected.
- 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.
- 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.
- Limiter: Limiter passes signals below a specified input level unaffected or gently reduced, while preventing the peaks of stronger signals from exceeding this threshold. Mastering engineers often use this type of dynamic range compression combined with make-up gain to increase the perceived loudness of an audio recording during the audio mastering process.
- Loudness Normalization: Normalizes for loudness and RMS, changes the level of the audio (normally reduce it to recommended limits). It is based on EBU R 128 recommendations on limiting the loudness of audio signals.
- 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.

### Fading

These fade a section in or fade it out:

- Adjustable Fade: enables you to control the shape of the fade (non-linear fading) to be applied by adjusting various parameters; allows partial (that is not from or to zero) fades up or down.
- Crossfade Clips: Use Crossfade Clips to apply a simple crossfade to a selected pair of clips in a single audio track.
- Crossfade Tracks: Use Crossfade Tracks to make a smooth transition between two overlapping tracks one above the other. Place the track to be faded out above the track to be faded in then select the overlapping region in both tracks and apply the effect.
- Fade In: Applies a linear fade-in to the selected audio - the rapidity of the fade-in depends entirely on the length of the selection it is applied to. For a more customizable logarithmic fade, use the Envelope Tool on the Tools Toolbar.
- Fade Out: Applies a linear fade-out to the selected audio - the rapidity of the fade-out depends entirely on the length of the selection it is applied to. For a more customizable logarithmic fade, use the Envelope Tool on the Tools Toolbar.
- Studio Fade Out: Applies a more musical fade out to the selected audio, giving a more pleasing sounding result.

For a discussion of what the different types of fade do, see Fades.

### Pitch and Tempo

These make the sound faster, slower, lower pitched or higher pitched:

- Change Pitch: Change the pitch of a selection without changing its tempo.
- Change Speed and Pitch: Change the speed of a selection, also changing its pitch.
- Change Tempo: Change the tempo and length (duration) of a selection without changing its pitch.
- 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 Stretch rather than Paulstretch for tasks like slowing down a song to a "practice" tempo.
- Sliding Stretch: This effect allows you to make a continuous change to the tempo and/or pitch of a selection by choosing initial and/or final change values.

### EQ and Filters

These change the quality of the sound:

- Bass and Treble: Increases or decreases the lower frequencies and higher frequencies of your audio independently; behaves just like the bass and treble controls on a stereo system.
- Filter Curve EQ: Adjusts the volume levels of particular frequencies, using drawn curves
- Graphic EQ: Adjusts the volume levels of particular frequencies, using sliders.
- High-Pass Filter: Passes frequencies above its cutoff frequency and attenuates frequencies below its cutoff frequency.
- Low Pass Filter: Passes frequencies below its cutoff frequency and attenuates frequencies above its cutoff frequency.
- Notch Filter: Greatly attenuate ("notch out") a narrow frequency band. This is a good way to remove mains hum or a whistle confined to a specific frequency with minimal damage to the remainder of the audio.
- Shelf Filter: A shelf filter curve is flat at both ends rather than flat only at the frequencies being passed.
- Classic Filters: Offers three different types of filter which together emulate the vast majority of analog filters, providing a useful graphical tool for analysis and measurement.

  The Classic Filters effect is not enabled by default. To enable it, use Effect > Plugin Manager to open the Plugin Manager dialog.

### Noise Removal and Repair

- Click Removal: Click Removal is designed to remove clicks on audio tracks and is especially suited to declicking recordings made from vinyl records.
- Clip Fix: Clip Fix attempts to reconstruct clipped regions by interpolating the lost signal.
- Noise Gate: Reduces the level of sound below a specified threshold level. >A noise gate is a kind of "dynamics processor" that allows audio above a specified threshold level to pass through unaffected (gate "open"), and stops or reduces sounds below the threshold level (gate "closed").
- Noise Reduction: This effect is ideal for reducing constant background noise such as fans, tape noise, or hums. It will not work very well for removing talking or music in the background. More details here.
- Repair: Fix one particular short click, pop or other glitch no more than 128 samples long.

### Delay and Reverb

These add reverberation or echo to your audio:

- Delay: A configurable delay effect with variable delay time and pitch shifting of the delays.
- Echo: Repeats the selected audio again and again, normally softer each time and normally not blended into the original sound until some time after it starts. 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.
- Reverb: A configurable stereo reverberation effect with built-in and user-added presets. It can be used to add ambience (an impression of the space in which a sound occurs) to a mono sound. Also use it to increase reverberation in stereo audio that sounds too "dry" or "close".

For details of the underlying principles of delay and reverb effects please see this page in the Wiki.

### Distortion and Modulation

- Distortion: Use the Distortion effect to make the audio sound distorted. By distorting the waveform the frequency content is changed, which will often make the sound "crunchy" or "abrasive". Technically this effect is a waveshaper. The result of waveshaping is equivalent to applying non-linear amplification to the audio waveform. Preset shaping functions are provided, each of which produces a different type of distortion.
- 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).
- 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.
- Vocoder: Synthesizes audio (usually a voice) in the left channel of a stereo track with a carrier wave (typically white noise) in the right channel to produce a modified version of the left channel. Vocoding a normal voice with white noise will produce a robot-like voice for special effects.
- Wahwah: Rapid tone quality variations, like that guitar sound so popular in the 1970's.

### Special

- Invert: This effect 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.
- Repeat: Repeats the selection the specified number of times.
- Reverse: Reverses the selected audio; after the effect the end of the audio will be heard first and the beginning last.
- Truncate Silence: Automatically try to find and eliminate audible silences. Do not use this with faded audio.

### Spectral Tools

These require your audio to be in Spectrogram view:

- Spectral Delete: Deletes the spectral selection from the audio.
- Spectral Edit Multi Tool: When the selected track is in spectrogram or spectrogram log(f) view, applies a notch filter, high- pass filter or low pass filter according to the spectral selection made. This effect can also be used to change the audio quality as an alternative to using Filter Curve EQ or Graphic EQ.
- Spectral Edit Parametric EQ: When the selected track is in spectrogram or spectrogram log(f) view and the spectral selection has a center frequency and an upper and lower boundary, performs the specified band cut or band boost. This can be used as an alternative to Filter Curve EQ and Graphic EQ or may also be useful to repair damaged audio by reducing frequency spikes or boosting other frequencies to mask spikes.
- Spectral Edit Shelves: When the selected track is in spectrogram or spectrogram log(f) view, applies either a low- or high-frequency shelving filter or both filters, according to the spectral selection made. This can be used as an alternative to Filter Curve EQ and Graphic EQ or may also be useful to repair damaged audio by reducing frequency spikes or boosting other frequencies to mask spikes.

## Generators by Function

See the Generate Menu for further details.

### Generate Tones

- Chirp: Generates four different types of tone waveform like the Tone Generator, but additionally allows setting of the starting and ending amplitude and frequency.
- DTMF Tones: Generates dual-tone multi-frequency (DTMF) tones like those produced by the keypad on telephones.
- Tone: Generates one of four different tone waveforms: Sine, Square, Sawtooth or Square (no alias), and a frequency between 1 Hz and half the current Project Sample Rate.

### Generate Silence or Noise

- Noise: Generates 'white', 'pink' or 'brown' noise.
- Silence: Creates audio of zero amplitude, the only configurable setting being duration.

### Generate Instruments or Metronome

- Rhythm Track: Generates a track with regularly spaced sounds at a specified tempo and number of beats per measure (bar).
- Pluck: A synthesized pluck tone with abrupt or gradual fade-out, and selectable pitch corresponding to a MIDI note.
- Risset Drum: Produces a realistic drum sound.

### Generate from Imported Data

- Sample Data Import: Create audio from imported numeric data.

## Analyzers by Function

See the Analyze Menu for further details.

### Analyze Amplitude or Other Audio Properties

- Contrast: Analyzes a single mono or stereo speech track to determine the average RMS difference in volume (contrast) between foreground speech and background music, audience noise or similar. The purpose is to determine if the speech will be intelligible to the hard of hearing.
- Find Clipping: Displays runs of clipped samples in a Label Track, as a screen-reader accessible alternative to View > Show Clipping. A run must include at least one clipped sample, but may include unclipped samples too.
- Measure RMS: A simple analyzer to measure the RMS (Root Mean Square) levels in a track.
- Plot Spectrum: Takes the selected audio (which is a set of sound pressure values at points in time) and converts it to a graph of frequencies against amplitudes.

The primary purpose of the "Measure RMS" plugin is to serve as an example for Nyquist Plugin Plugin writers, of how translations may be added to plugins.

### Divide Up Sounds or Silences using Labels

- Label Sounds: Is a tool which can useful to label the different songs or sections (or silences) in a long recording, such as the tracks from an LP or cassette.

### Mark Beats using Labels

- Beat Finder: Attempts to place labels at beats which are much louder than the surrounding audio. It's a fairly rough and ready tool, and will not necessarily work well on a typical modern pop music track with compressed dynamic range. If you do not get enough beats detected, try reducing the "Threshold Percentage" setting.

## Tools by Function

### Nyquist

- Nyquist Prompt: Brings up a dialog where you can enter Nyquist commands. Nyquist is a programming language for generating, processing and analyzing audio. For more information see Nyquist Plug-ins Reference.
- Nyquist Plug-in Installer The Nyquist Plug-in Installer is itself a Nyquist plugin that simplifies the installation of other Nyquist plugins.

### Divide Up audio using Labels

- Regular Interval Labels: Places labels in a long track so as to divide it into smaller, equally sized segments.

### Data export and import

- Sample Data Export Reads the values of successive samples from the selected audio and prints this data to a plain text, CSV or HTML file. Further information may be added as a "header" at the top of the file.
- Sample Data Import Reads numeric values from a plain ASCII text file and creates a PCM sample for each numeric value read.