View source for Other plug-ins and tools for fades

==[[Other plug-ins and tools]]==
{{Hint|Nyquist plug-ins extend the capabilities of Audacity and are supported on Windows, Mac and GNU/Linux. Instructions for installing Nyquist plug-ins can be found on our Wiki page  [http://wiki.audacityteam.org/wiki/Download_Nyquist_Plug-ins# Download Nyquist Plug-ins].}}

=== [http://wiki.audacityteam.org/wiki/Nyquist_Effect_Plug-ins#Fade_In_and_Out Fade In and Out] ===
This is a Nyquist plug-in that can apply a linear fade in and fade out to the selected audio.

This tool was written by [http://www.garyallendj.com/davidsky/index.html David R Sky] to provide a simple, accessible way for visually impaired and other non-mouse users to apply fade in and out effects. The current Audacity 2.x has a Selection Toolbar providing a screen-reader friendly display of selection start time and duration (* except on Linux) which can be used for similar purpose, but this effect may be found to be quicker and easier to use.

=== [http://wiki.audacityteam.org/wiki/Nyquist_Effect_Plug-ins#Text_Envelope Text Envelope] ===
This is a Nyquist plug-in that can apply multiple changes to the amplitude of the selected audio, fading from one level to another as required.

This tool was written by Steve Daulton to provide an accessible alternative to the "Envelope Tool" for visually impaired and other users that do not use pointing devices.

=== Creating Fades from the Nyquist Prompt ===
[http://audacity.sourceforge.net/help/nyquist Nyquist] is a programming language that is included in Audacity. It can be used to write [[Effect Menu#Nyquist_Effects|plug-ins]] for Audacity that may provide new effects, generators and analysis plug-ins. Nyquist commands may also be run directly in Audacity by entering code into the [[Effect Menu#Nyquist|Nyquist Prompt]] Effect. Below are a few short code samples that may be run in the Nyquist Prompt to produce fades to selected audio. More information about Nyquist programming may be found in the [http://wiki.audacityteam.org/wiki/Nyquist_Audio_Programming Nyquist Audio Programming] and [http://wiki.audacityteam.org/wiki/Nyquist_Plug-ins_Reference Nyquist Plug-ins Reference] sections of the Wiki.

 ; Linear Fade Out:
 (mult s (pwlv 1 1 0))

 ; Linear Fade In.
 ; To avoid a click at the end, the pwlv envelope
 ; extends beyond the end of the selection.
 (mult s (pwlv 0 1 1 1.1 1))

 ; Multi-step fade out.
 (mult s (pwlv 1 0.4 0.775 0.8 0.447 0.9 0.316 0.95 0.224 1.0 0.0))

 ; sine curve fade in:
 (mult s 0.5
   (sum 1
     (osc (hz-to-step (/ (get-duration 2)))
       1 *table* -90)))

 ; wiggly fade:
 (setf wiggle (mult 0.2 (hzosc (/ 6.0 (get-duration 1)))))
 (mult s (sum 1.0 wiggle))


===Removing a click from the start of a sound===
{{Hint| When editing sounds, clicks can often be avoided by ensuring that edit points occur at [[Edit Menu#zero|zero crossing points]] (where the waveform crosses the center zero line).}}
If a sound starts suddenly, there will often be a noticeable click at the beginning. This is due to the waveform suddenly jumping from silence to the start of the waveform. This "jump" is often visible by [[Zooming|zooming]] in closely on the start of the sound so you can see the original sample dots:
:<span title="Audio starts at non-zero">[[Image:Click-at-start.png|link=]]</span>

Applying a short, linear fade in can eliminate the click by smoothing the transition from silence to the start of the sound.
:<span title="Fade in to eliminate click at start of audio">[[Image:Fade-in-start.png|link=]]</span>

===Adding an extract of music to a presentation===
Whether Powerpoint, OpenOffice Impress, a slide show for YouTube or any other audio-video presentation, it is often desirable to include audio clips within the presentation. Rather than simply cutting a recording to the required length, applying a fade in and fade out to the audio clip can add a touch of professionalism to the production.

The duration of the fade as well as the shape of the fade are crucial to the overall effect. Typically an audio clip will have a relatively short fade in and a longer fade out, but there are no hard and fast rules. Audacity allows you to experiment with different fade lengths. When preparing audio clips for use in your presentation you can export several versions with differing fade lengths, then when putting together the presentation, try your alternative versions and use whichever you most like.

Fading in music with an [[#Exponential_Fade|exponential shape fade]] is often very effective as you get a hint of the music first, then it rapidly fades to full volume. For fading out music, a [[#Sine_Curve_Fade|sine curve fade]] often works well.

See also: [[Mixing]]