Delete with Crossfade

Malcolm Sharpe and Bruce Sharpe
Copyright (c) 2005 Singular Software

Overview

This is a plug-in for Audacity that combines the operation of delete and crossfade. This makes it easy to seamlessly eliminate segments of sound.

Here's what it does. In the image below, the yellow bar represents a waveform. The blue part is a selection to be deleted.

After deletion, a portion of the selection is kept at each end. The amount retained is the crossfade length.

The end pieces are linearly ramped to zero

and then mixed together.

If you don't have it already, download and install Audacity.
The plug-in is a single file, deletewithcrossfade.ny. Download this into the Audacity plug-ins folder (usually C:\Program Files\Audacity\Plug-Ins).

There is a screencast showing how to use this plug-in.
First select the region to delete. Note that the selection should extend a little beyond the exact boundaries of the sound to be deleted.
Choose Effect -> Delete With Crossfade from the menu.
In the dialog box, change the Crossfade length if you'd like. A long crossfade (2 or more seconds) is used when you'd like to hear the smooth transition between sounds. A short crossfade (such as the default 0.1 seconds) is typically used to hide the fact that there is a cut at all.

The Debug button results in a dialog showing after processing is complete. The information presented is mainly of interest to programmers who are modifying the code.
Note that if you want to do a series of deletes with crossfade in succession, you can use the keyboard shortcut Ctrl-R to repeat the last effect with the same parameters.

It would be better if the crossfade region was taken from outside the selection instead of inside. However this is not possible because plug-in scripts in Audacity cannot access any samples outside the selection.
Only a linear crossfade is offered. Several others are in common use (quadratic, logarithmic, sinusoid).