Effect Menu
Classes of Effect
There are four classes of effects - the built-in Effects, and three classes of plug-in effect which allow you to download and install additional effects. All classes of effect are applied in the same way. The four effects classes are:
Mac users also have access to Audio Unit effects. Do we want to note that here, or further down under LADSPA effects?
- Built-in Effects
- VST Effect Plug-ins
- Nyquist Effect Plug-ins
- LADSPA Effect Plug-ins
Purpose of Effects
Effects in any of the four classes can perform similar tasks. These are Audacity's built-in effects grouped by purpose:
Volume changes
(no effect on tone quality)
Amplify Auto Duck Compressor Fade In Fade Out Leveller Normalize To Do: create additional links
Tone changes
Bass Boost Echo Equalization Phaser Wahwah To Do: create additional links
Pitch and tempo changes
Change Pitch without changing tempo; Change Tempo without changing pitch; Change Speed affecting pitch and tempo
Audio restoration
Click Removal Noise Removal Repair Truncate Silence To Do: create additional links
Other built-in effects
Invert Repeat Nyquist Prompt Reverse To Do: create additional links
Generate and Analyze plug-ins
Nyquist plug-ins are also used to provide some of Audacity's built-in audio generators and analysis tools. You can similarly add either Nyquist or LADSPA generation and analysis plug-ins to Audacity which will then appear under the Generate or Analyze Menu.
List of Built-in Effects
Amplify...
This effect 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.
BassBoost...
This is a smooth filter which can amplify the lower frequencies while leaving most of the other frequencies alone. It behaves just like the bass control on a stereo.
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 individual clicks on audio tracks and is especially suited to declicking recordings made from vinyl records, without damaging the rest of the audio.
Compressor...
Compresses the dynamic range by making the soft parts louder, and the loud parts softer.?????? More details here
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 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.
Do we want this image here? It is NOT showing the use of the envelope tool as implied by the preceding text. I don't think we need images for these simple fade effects, and I don't think they need their own pages. - Bill
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 example when the left and right channels of a song both contain equal amounts of vocals, but unequal amounts of background instruments. By inverting one of the channels and not the other and then converting from stereo to mono, the vocals will cancel each other out, leaving just the instrumentals. This only works if the exact same vocal signal is present in both of the channels to begin with.
Leveller...
The Leveller effect makes quiet passages louder and loud passages quieter. It does this in a way that is different from the Compressor effect. As a result it does add some distortion to the processed audio. The only way to be sure if the effect does what you want is to try it. For example, applying this effect twice at its Heaviest setting on a normally-recorded voice can produce an "air traffic controller" effect.
Noise Removal...
This effect is ideal for removing 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.
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...
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 very short click, pop, or other glitch no more than 128 samples long.
Repeat...
Repeats the selection the specified number of times.
Reverse
This effect reverses the selected audio temporally; after the effect the end of the audio will be heard first and the beginning last. Some people reverse small portions of audio to make inappropriate language unintelligible, while others believe you can hear subliminal messages if you listen to speech backwards. You can also create interesting sound effects by recording natural events and reversing the audio.
Sliding Time Scale / Pitch Shift
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.
This effect 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 WahWah effect automatically adjusts the phase of the left and right channels when given a stereo recording, so that the effect seems to travel across the speakers.
VST Effects
- To use a VST plug-in effect, put the effect in the directory (folder) called "Plug-Ins", which should be in the same directory where Audacity resides. If there is no directory, create one.
- You will also need to download and unzip the [Enabler] To do: broken link to the same directory.
- The next time you launch Audacity, any plug-ins you added will appear in the Effect menu.
Nyquist Effects
- To use a Nyquist effect, put the effect in the directory (folder) called "Plug-Ins", which should be in the same directory where Audacity resides. Upon installation, some nyquist scripts are included, so you needn't worry about creating this directory.
- The next time you launch Audacity, any plug-ins you added will appear in the Effect, Generate or Analyze menus.
Clip Fix ...
Clip Fix attempts to reconstruct clipped regions by interpolating the lost signal.
Cross Fade In
Despite the name this effect does not do an automatic cross fade between two tracks or clips. Instead it applies a curve that is different from the one used by the Fade In effect. The curve used is one that will result in equal volume throughout the fade once the faded in and faded out regions are mixed.The details of how to use this in conjunction with the Cross Fade Out effect to make equal-volume cross fades is left as an exercise for the reader ? - Bill
Cross Fade Out
Despite the name this effect does not do an automatic cross fade between two tracks or clips. Instead it applies a curve that is different from the one used by the Fade Out effect. The curve used is one that will result in equal volume throughout the fade once the faded in and faded out regions are mixed.The details of how to use this in conjunction with the Cross Fade In effect to make equal-volume cross fades is left as an exercise for the reader ? - Bill
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.
Low Pass Filter...
Passes frequencies below its cutoff frequency and attenuates frequencies above its cutoff frequency.
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
Attempts to remove center-panned vocals from a stereo track. Help text is available from within the dialog.
Vocoder
LADSPA Effects
These originally started out in a Linux plugin format under the Linux Audio Developer's Simple Plugin API, but can now be used in Windows and OS X as well. There are lots of free plugins available, and no enabler is needed. More information can be found ladspa.org and the Audacity Plug-ins and Libraries page.
Getting a good reverb sound depends a lot on the source audio and can take a lot of experimentation. One good strategy is to select a small portion of audio (a few seconds) and try to add reverb. Listen to it, then Undo and try it again with different settings. Keep doing this until you've found the settings you like the sound of best, and then Undo one last time, Select All, then apply the effect to your entire recording.
