Download the “Audio Tools for Xcode” package by going to Xcode > Open Developer Tool > More Developer Tools ...
Install the CoreAudio folder found in the “Audio Tools for Xcode” package. Make sure to grab the one from Feb. 16, 2012. The Xcode packages assume it’s in the folder /Applications/Developer. If you install it somewhere else, change the CORE_AUDIO_LOCATION setting in the Xcode projects
Building an AudioUnit
Duplicate the provided MyAU project with the command: python duplicate.py MyAU (For example: python duplicate.py MyAU YourAU MyCompany)
Open a gen~ patch to be turned into a plugin.
Send gen~ the exportcode message in order to export the genpatcher as C++ code.
Open the Xcode project generated in step 2.
Change the COMP_MANUF [It must be 4 letters] and COMP_SUBTYPE settings in the .r resource file and the -Info.plist file.
If you installed CoreAudio in a location other than /Applications/Developer, change the CORE_AUDIO_LOCATION build setting to the appropriate location and change the location of all of the files in the CoreAudio folder so that Xcode can compile them.
Click on the project in the Project Navigator to show the build settings
Click on the target under the Targets section
If not already showing, click on the Build Settings tab
Under the User-Defined section, see the CORE_AUDIO_LOCATION setting to be changed (you can use the search field in the Build Settings to quickly locate it)
Build the project.
Copy the build product to the /Library/Audio/Plug-Ins/Components folder.
Run auval -a to verify that the plugin functions properly.