Logic Express can act as a host for (compliant, correctly installed and authorized) Audio Units effect and instrument plug-ins from other manufacturers.
Important: Logic Express cannot act as a host for plug-ins in VST or RTAS format. There are, however, utilities such as the VST to Audio Units Adapter (http://www.fxpansion.com), that “wrap” Mac OS X versions of VST plug-ins to create virtual Audio Units. Once wrapped, most of these plug-ins behave, and can be used, just like Audio Units.
Many plug-ins from other manufacturers use a proprietary storage format for their presets (the equivalent of Logic Express plug-in settings).
In most cases, a separate Preset (or similarly named) menu will be available in the plug-in interface. Once loaded, you can save any of these presets as a Logic Express setting.
In all cases, the global Compare, Copy, and Paste options of the plug-in window header will work as they do with the native plug-ins of Logic Express.
Logic Express uses the Apple AU Validation Tool to ensure that only plug-ins that fully comply with the Audio Units specification are used in Logic Express. This minimizes problems that may be caused by third-party Audio Units plug-ins.
The validation process takes place automatically when:
Logic Express is first opened.
An updated version of Logic Express is installed.
You install new Audio Units plug-ins, or update existing ones.
You can see the results of the validation scan (for all Audio Units and “wrapped” VST plug-ins) in the Compatibility column of the Audio Units Manager window.
Important: The first thing you should do is check the manufacturer’s website for updated versions of Audio Units plug-ins that fail validation.
Choose Logic Express > Preferences > Audio Units Manager in the main menu bar (or use the Audio Units Manager key command).
Audio Units plug-ins that fail the validation test can be manually activated by selecting the checkboxes in the Logic column—but be aware that these plug-ins can cause problems.
If you encounter problems with manually activated failed plug-ins, click the Disable Failed Audio Units button in the Audio Units Manager window.
Warning: Use of plug-ins that have failed the validation can negatively affect the test results of subsequently scanned plug-ins. They can also prevent Logic Express from opening, cause it to quit unexpectedly, or even lead to data loss (destroyed project files).
The Audio Units Manager also allows you to disable Audio Units plug-ins that you don’t want to use in Logic Express, even if they pass the validation scan. Simply deselect the corresponding checkbox in the Logic column to disable any plug-in. You can store your choice of Audio Units plug-ins by clicking the Done button.
Click the Reset & Rescan Selection button to rescan a selection of plug-ins after installing plug-ins/updaters or moving components in the Finder, while Logic Express or the Audio Units Manager is open. They will be activated automatically, if they pass the validation scan.
Note: If you press Control-Shift while opening Logic Express, the Audio Units Safe mode will be used. Only plug-ins that pass the validation test will be available; manually activated plug-ins that failed the validation test will not be available.