Other plug-ins and tools for fades - Audacity Development Manual

# Other plug-ins and tools for fades

From Audacity Development Manual

This page lists some downloadable or more advanced tools for making fades.

## Contents

1. Fade In and Out
2. Text Envelope
3. Creating Fades from the Nyquist Prompt

## Fade In and Out

This is a Nyquist plug-in that can apply a linear fade in and fade out to the selected audio.

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 Download Nyquist Plug-ins.

This tool was written by 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.

## 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

Nyquist is a programming language that is included in Audacity. It can be used to write 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 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 Nyquist section of the Wiki.

The code examples below require that the "Legacy (version 3) syntax" option is selected

    ; 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))

The above examples may be run without the "Legacy (version 3) syntax" option selected if the S parameter is replaced with *track*. One example using version 4 syntax is given below.

    ; wiggly fade out (version 4 syntax):
    (setf wiggle (mult 0.2 (hzosc (/ 6.0 (get-duration 1)))))
    (mult *track* (pwlv 1 1 0) (sum 1.0 wiggle))