### Adding and Editing AU Generators

Summary: This section describes how to add a Generator input track to the document and how to edit an existing generator track. An AU Generator is an Audio Unit that generates audio from an audio file, or algorithmically To add a generator to the document, select Add AU Generator… from the Edit menu. To edit an existing generator, double-click on the generator group's title bar, or select the generator group and choose Edit Selected Group… from the Edit menu. The Add Audio Unit Generator sheet provides facilities for specifying the Audio Unit to be used for the generator. There are two modes of operation: basic and advanced (toggled via the Show/Hide Audio Unit Details disclosure triangle). The advanced edit mode provides more detailed Audio Unit configuration facilities.

An AU Generator is an Audio Unit that generates audio from an audio file, or algorithmically. Apple ships a generator named AUAudioFilePlayer that can playback audio stored in audio files on disk.

To add a generator to the document, select Add AU Generator… from the Edit menu. To edit an existing generator, double-click on the generator group's title bar, or select the generator by clicking on it to highlight the track and choose Edit Selected Group… from the Edit menu.

The Add Audio Unit Generator sheet is nearly identical to the Edit Audio Unit Generator sheet except that the add sheet allows you to specify the generator Audio Unit.

Add AU Generator sheet with details hidden

The Add Audio Unit Generator sheet has two modes: a basic mode (as shown in the image above) and an advanced mode that provides more detailed Audio Unit configuration. In the basic mode, the sheet contains the following items:

Color Well: Displays the current group color. When clicked, this color well invokes the standard Apple color picker and allows the user to choose a new color.

AU Source popup menu (Add Audio Unit Generator sheet only): Selects the AU that will be used for the track. AU Generators are sorted in a hierarchical menu grouped by manufacturer.

Show/Hide Audio Unit Details disclosure triangle: Toggles between basic and advanced editing mode. Basic mode is the default mode, but the sheet will remember the mode that it was left in.

Add AU Generator sheet with details visible

The visual appearance of the advanced mode similar to the AU Instrument configuration section but it only presents an output settings section since AU Generators do not support audio input. See Configuring Fixed Outputs for information on editing the outputs of an AU Generator that supports a fixed number of outputs. See Configuring Variable Outputs for an AU Generator that supports a variable number of outputs.