Index of Effects, Generators, Analyzers and Tools - Audacity Manual

# Index of Effects, Generators, Analyzers and Tools

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

- Effects change the audio in some way.
  - Note that 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.

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.

| 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

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

| There is a special conversion tool EQ XML to TXT Converter to convert an XML file of exported EQ (equalization) presets made from The Equalization effect in older versions of Audacity to the TXT text file required by Graphic EQ and Filter Curve EQ.

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.

## Add / Remove Plug-ins...

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 plug-ins, you can use this to make the Effect menu shorter or longer as required. For details see Add / Remove Effects, Generators and Analyzers.

By default all the built-in effects, with the exception of Classic Filters, are enabled in Audacity.

Additional plug-ins can also be loaded into Audacity:

- Installing Nyquist plug-ins on Windows, Mac or Linux
  - See also this list of downloadable Nyquist plug-ins
- Installing VST plug-ins on Windows, Mac or Linux
- Other types of plug-in.

## 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.

### 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.

### Fade a section in or fade it out

- 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.
- 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.

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

### 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.
- 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 > Add / Remove Plug-ins... to open the Plug-in Manager dialog.

- 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.
- 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.
- 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").
- 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.
- 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).
- Spectral Delete: Deletes the spectral selection from the audio.
- 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.
- 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.

### Repair damaged audio

- 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 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.
- 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.
- Repair: Fix one particular short click, pop or other glitch no more than 128 samples long.
- 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.

### Make the sound faster, slower, lower pitched or higher pitched

- Change Pitch: Change the pitch of a selection without changing its tempo.
- Change Speed: 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.
- 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.
- 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.
- Truncate Silence: Automatically try to find and eliminate audible silences. Do not use this with faded audio.

### Add reverberation or echo

- 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.

### Remove vocals

- Vocal Reduction and Isolation: Attempts to remove or isolate center-panned audio from a stereo track. Most "Remove" options in this effect preserve the stereo image.
- 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.

### Manipulate Audio

- 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.

## 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 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" plug-in is to serve as an example for Nyquist Plug-in Plug-in writers, of how translations may be added to plug-ins.

### 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 plug-in that simplifies the installation of other Nyquist plug-ins.

### 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.