Unify doesn't produce any sound by itself. It relies on plug-ins to produce and modify sound. Unify includes a substantial set of plug-ins, some of which are actually built into the program, and can also work with just about any other plug-ins you own.

Unify can deal with three categories of plug-ins:

• Built-in plug-ins are part of the Unify program itself
• Bundled plug-ins include free and/or open-source instruments and effects, whose authors/developers/maintainers have given us permission to distribute with Unify.
• Other plug-ins you own includes just about all the plug-ins now on your system, and others you may buy later.

Click here for the full list of plug-ins included with Unify.

As you may know, plug-ins also come in various, mutually-incompatible formats. Unify can load any of the following three formats (Audio Units is Mac-only):

• VST (“virtual studio technology”) was developed by Steinberg Media Technologies GmbH.
• VST3 (VST version 3) is a newer format also developed by Steinberg.
• Audio Units (AU) is a format developed by Apple Corporation.

There are a handful of other formats which Unify cannot use, most notably AAX (Avid Audio eXtension), a proprietary format developed by Avid Technology, Inc. for use with their Pro Tools DAW.

Unify itself comes as a stand-alone app and as a plug-in, in VST, VST3, Audio Unit, and AAX formats.

Unify maintains a simple database of plug-ins it knows about, which includes details like the plug-in name, manufacturer name, format (e.g. VST, AU, etc.), and the path to the folder where the plug-in is stored.

You can inspect the contents of this database by clicking on the plug icon near the bottom-right corner of the Unify GUI (highlighted in blue-green in the following screenshot). This is called the plug-ins view. (Note some details, such as folder paths, don't appear in this view, but they are still present in the database.)

This plug-in database is automatically populated with details about Unify's built-in and bundled plug-ins, but other plug-ins on your computer must be registered with Unify, so it can add them to its database. This can be done in either of two ways:

1. Drag-and-drop: To register one or a few plug-ins at a time, locate the plug-in file(s) and drag its icon directly onto Unify's plug-ins view.
2. Scan: You can also have Unify scan your system to locate plug-ins, as described on the page Scanning and using your own plug-ins.

Clicking on the Operations button at the bottom of the Known Plug-Ins view pops up a menu like this:

The functions available (as of Unify v1.6.0) are:

• Clear list: Remove ALL scanned plug-ins from the list, leaving only the built-in and bundled plug-ins. Don't click this. It's only there for certain tech-support situations.
• Remove all … plug-ins: Remove scanned plug-ins of specific types. (On Mac, an item for Audio-Units will also appear.)
• Remove selected plug-in(s) from list: Allows you to select one or more plug-ins by clicking them in the list, and then remove only those.
• Remove any plug-ins whose files no longer exist: If you have manually removed any files from your system's plug-ins folders, this will ensure that your Known Plug-Ins list will no longer have phantom entries referring to files you have removed (or renamed).
• Remove “redundant” plug-ins: Attempts to remove extra versions of plug-ins as follows:
  • Remove VST3 versions of every plug-in for which a plain VST version exists.
  • On a Mac, first remove Audio-Unit versions of any plug-in for which a VST or VST3 version exists.
• Show folder containing selected plug-in: This item will be available when you select exactly one plug-in from the list. (You can also access it by right-clicking the list entry.) It allows you to see where Unify will look when attempting to load the selected plug-in.
• Scanning… items: See Scanning and using your own plug-ins.

Note all the Remove… items and Clear List will pop up an “are you sure” dialog, allowing you to cancel.