AU - AudioUnits
Apple’s proprietary audio technology, part of the Core Audio provided by Mac X OS. It is part of the operating system so it provides low latency and system-level support for the interface. Most DAWs developed for Mac OS X support the Audio Units interface due to its stability and system-level solutions (which also means faster processing). Apple Logic only utilises Audio Unit format plugins, but other DAWs such as Ableton can also use these.