Effect Menu: Audio Unit

Peter 20Apr17: Apple refers to these as "Audio Units" - thus so should we (and BTW we have, up to now, not been consistent in this respect). For example see this page of Apple documentation.

• Gale 20Apr17: I thought in the past that Apple did refer to a single plugin as an "Audio Unit". So is the upshot that you have corrected this here but seek a wording change in Audacity?
  • Peter 20Apr17: ha Gale: I have subsequently found this page with a bit more research: https://developer.apple.com/library/content/documentation/MusicAudio/Conceptual/AudioUnitProgrammingGuide/Introduction/Introduction.html where Apple clearly refer to Audio Unit in the singular.

    So I'll go back and rework the AU effects page etc. - and thus we will not need to word-change the app.

  • Peter 21Apr17: I discussed this at length with my "mystery shopper" who is multi-lingual and holds a Masters in Linguistic Studies - she came down in favor of the singular usage, commenting that we do not have LAPSPAs effects or Nyquists effects. The usage in the Audacity app in the singular too as you will only ever select a single effect from the Effect menin Grouped by Type mode. If we want to refer mutiples then that would be more correctly stated as "Audio Unit effects" (I'm assuming that Apple's use, inconsistent as it is, of "Audio Units" actually is shorthand for "Audio Unit effects"). Removed the P1.

Audio Unit (AU) is a system-level plugin architecture provided on Mac computers.

Import/export of presets is supported (see the description below of how it works) and the saving of presets for use in Audacity only.

Adding Audio Unit effects

For detailed instructions on installing Audio Unit plugins for Audacity see: Installing Effect, Generator and Analyzer plugins on Mac.

Please note that not all of the Audio Unit effects that Apple supplies can be enabled in Audacity. AU instruments are not supported even if they can be enabled. They will show listed as available in the New section of the Plugin Manager but if you try to enable them you will get an error message telling you that they failed to register. This is an Apple issue and not an Audacity bug. This only affects a few of the Audio Unit plugins: AUScheduledSoundPlayer, AUMultiSplitter, AUMultiChannelMixer, AUMixer3D, AUMIxer, AUMatrixMixer, AUAudioFilePlayer and AUSpeechSynthesis.

Saving, Exporting and Importing Audio Unit Effect Presets

Save Preset...

To save the current effect settings as a User Preset, select Save Preset... from the Manage menu in the effect dialog which brings up the following dialog:

Type a name for the preset then click OK after which the saved preset will appear in the "User Presets" list in the Manage menu.

Export...

Before you can export a preset you must already have saved it as a User Preset.

Each preset for Audio Unit effects is exported to a separate ".aupreset " file at /Users/<yourUserName>/Library/Audio/Presets/Apple/<effectName>/. A presets file lets you move settings for a particular effect between computers.

To export a saved User Preset, select Export... from the Manage menu   in the effect dialog which brings up the following dialog:

Select the user preset(s) you want to export then click OK to export each selected preset to a file. If there is only one preset in the list you must still select it, or nothing will be exported.

Import...

Select Import... from the Manage menu in the effect dialog which brings up the following dialog:

Select the preset(s) you want to import then click OK to import each preset file as a User Preset.

Importing one or more presets does not load new settings into the effect. You must select one of the imported presets from User Presets... in the Manage menu   to load its settings into the effect.

Audio Unit Effect Options

In the effect's dialog, click the Manage button then choose Options...   to bring up the dialog illustrated below. When you change the options in this dialog, the changes apply only to the current effect that is open. All other Audio Unit effects will remain at the default options shown below until you change their options.

• Latency Compensation: This setting (enabled by default) compensates for waveform delay caused by Audio Unit effects which preload audio data to a buffer. Compensation may not work in all cases, and for it to work, any compensation or latency reporting settings in the effect itself must be enabled. If compensation fails or if this Audacity setting is unchecked, effects that buffer audio will insert silence at the start of the processed selection and remove a corresponding amount of audio from the end of the selection. Enabling or disabling compensation is effective immediately.
• User Interface: The "Full" setting, enabled by default, allows most Audio Unit effects to display a graphical (instead of a plain text) interface. If you change this setting you must close the settings dialog, then close and reopen the effect to see the change.

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