Audio Units
Encyclopedia
Audio Units are a system-level plug-in architecture provided by Core Audio
in Mac OS X
developed by Apple Computer
. Audio Units are a set of application programming interface
services provided by the operating system
to generate, process, receive, or otherwise manipulate streams of audio in near-real-time with minimal latency. It may be thought of as Apple's architectural equivalent to the other popular plug-in format, Steinberg
's VST
. Because of the many similarities between Audio Units and VST several commercial and free wrapping technologies are available (e.g. Symbiosis and FXpansion
VST-AU Adapter).
an audio file, convert its sample rate and stream audio over a Local Area Network
. It also comes with a collection of AU plug-ins such as EQ filters, dynamic processors, delay, reverb, and a Soundbank Synthesizer Instrument.
AU are used by Apple applications such as GarageBand
, Soundtrack Pro
, Logic Express
, Logic Pro
, Final Cut Pro
, MainStage
and most 3rd party audio software developed for Mac OS X such as Ardour
, Ableton Live
, REAPER
and Digital Performer
.
Core Audio
Core Audio is a low-level API for dealing with sound in Apple's Mac OS X and iOS operating systems. It includes an implementation of the cross-platform OpenAL library....
in Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
developed by Apple Computer
Apple Computer
Apple Inc. is an American multinational corporation that designs and markets consumer electronics, computer software, and personal computers. The company's best-known hardware products include the Macintosh line of computers, the iPod, the iPhone and the iPad...
. Audio Units are a set of application programming interface
Application programming interface
An application programming interface is a source code based specification intended to be used as an interface by software components to communicate with each other...
services provided by the operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
to generate, process, receive, or otherwise manipulate streams of audio in near-real-time with minimal latency. It may be thought of as Apple's architectural equivalent to the other popular plug-in format, Steinberg
Steinberg
Steinberg GmbH is a German musical software and equipment company based in Hamburg. It mainly produces music recording, arranging and editing software as used in digital audio workstations and VSTi software synthesizers.- History :...
's VST
Virtual Studio Technology
Steinberg's Virtual Studio Technology is an interface for integrating software audio synthesizer and effect plugins with audio editors and hard-disk recording systems. VST and similar technologies use digital signal processing to simulate traditional recording studio hardware with software...
. Because of the many similarities between Audio Units and VST several commercial and free wrapping technologies are available (e.g. Symbiosis and FXpansion
FXpansion
FXpansion is a Ltd company that produces music software including DCAM: Synth Squad, BFD, GURU and the VST-RTAS and VST-AudioUnit Adapters.- History :...
VST-AU Adapter).
Usage
Mac OS X comes with Audio Units allowing one to timestretchAudio timescale-pitch modification
Time stretching is the process of changing the speed or duration of an audio signal without affecting its pitch.Pitch scaling or pitch shifting is the opposite: the process of changing the pitch without affecting the speed...
an audio file, convert its sample rate and stream audio over a Local Area Network
Local area network
A local area network is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building...
. It also comes with a collection of AU plug-ins such as EQ filters, dynamic processors, delay, reverb, and a Soundbank Synthesizer Instrument.
AU are used by Apple applications such as GarageBand
GarageBand
GarageBand is a software application for Mac OS X and iOS that allows users to create music or podcasts. It is developed by Apple Inc. as a part of the iLife software package on Mac OS X.-Audio recording:...
, Soundtrack Pro
Soundtrack Pro
Soundtrack Pro was a music composing and audio editing application made by Apple Inc., which includes a collection of just over 5000 royalty free professional instrument loops and sound effects...
, Logic Express
Logic Express
Logic Express is a "light" version of Logic Pro, a MIDI sequencer and digital audio workstation software application maintained by Apple that runs on the Mac OS X platform. It was announced on 15 January 2004 for release in March 2004....
, Logic Pro
Logic Pro
Logic Pro is a hybrid 32 / 64 bit digital audio workstation and MIDI sequencer software application for the Mac OS X platform. Originally created by German software developer Emagic, Logic Pro became an Apple product when Apple bought Emagic in 2002...
, Final Cut Pro
Final Cut Pro
Final Cut Pro is a non-linear video editing software developed by Macromedia Inc. and then Apple Inc. The most recent version, Final Cut Pro X, runs on Mac personal computers powered by Mac OS X version 10.6.7 or later and using Intel processors...
, MainStage
Mainstage
Main stage theatre is that which falls between studio theatre and large-scale events. It is usually performed in a proscenium theatre or on a thrust stage. Main stage is also used to describe the performance space with the largest audience capacity at a performing arts festival or other venues.-...
and most 3rd party audio software developed for Mac OS X such as Ardour
Ardour (audio processor)
Ardour is a hard disk recorder and digital audio workstation application. It runs on Linux, Mac OS X and FreeBSD. Its primary author is Paul Davis, who is also responsible for the JACK Audio Connection Kit...
, Ableton Live
Ableton Live
Ableton Live is a loop-based software music sequencer and DAW for Mac OS and Windows by Ableton. The latest major release of Live, Version 8, was released in April 2009. In contrast to many other software sequencers, Live is designed to be an instrument for live performances as well as a tool for...
, REAPER
REAPER
REAPER is a digital audio workstation created by Cockos. It is distributed with an uncrippled evaluation license with a nag screen explaining the license cost. It is currently available for Microsoft Windows and Mac OS X...
and Digital Performer
Digital Performer
Digital Performer is a full-featured Digital Audio Workstation/Sequencer software package published by Mark of the Unicorn of Cambridge, Massachusetts for the Apple Macintosh platform.-Ancestry:...
.
Competing technologies
- DigidesignDigidesignAvid Audio is an American digital audio technology company. It was founded in 1984 by Peter Gotcher and Evan Brooks. The company began as a project to raise money for the founders' band, selling EPROM chips for drum machines. It is a subsidiary of Avid Technology, and during 2010 the Digidesign...
's Real Time AudioSuiteReal Time AudioSuiteReal-Time AudioSuite is a format of audio plug-in developed by Digidesign, currently Avid Technology for their Pro Tools LE, and Pro Tools M-Powered systems, although they can be run on Pro Tools HD and Pro Tools TDM systems. RTAS plug-ins use the processing power of the host computer rather than... - LADSPALADSPALADSPA is an acronym for Linux Audio Developers Simple Plugin API. It is a standard for handling filters and effects, licensed under the GNU LGPL. It was originally designed for Linux through consensus on the Linux Audio Developers Mailing List, but works on a variety of other platforms...
, DSSIDSSIDSSI is a virtual instrument plugin architecture for use by music sequencer applications. It was designed for applications running under Linux, although there is nothing specific to Linux in the interface itself...
and LV2LV2LV2 is an open standard for plugins and matching host applications, mainly targeted at audio processing and generation.LV2 is a simple but extensible successor of LADSPA, intended to address the limitations of LADSPA which many applications have outgrown.Currently there is support for LV2 in...
for LinuxLinuxLinux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds... - MicrosoftMicrosoftMicrosoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
's DirectXDirectXMicrosoft DirectX is a collection of application programming interfaces for handling tasks related to multimedia, especially game programming and video, on Microsoft platforms. Originally, the names of these APIs all began with Direct, such as Direct3D, DirectDraw, DirectMusic, DirectPlay,... - SteinbergSteinbergSteinberg GmbH is a German musical software and equipment company based in Hamburg. It mainly produces music recording, arranging and editing software as used in digital audio workstations and VSTi software synthesizers.- History :...
's Virtual Studio TechnologyVirtual Studio TechnologySteinberg's Virtual Studio Technology is an interface for integrating software audio synthesizer and effect plugins with audio editors and hard-disk recording systems. VST and similar technologies use digital signal processing to simulate traditional recording studio hardware with software... - JACKJACK Audio Connection KitJACK is a professional sound server daemon that provides real-time, low latency connections for both audio and MIDI data between applications that implement its API...
- Similar technology developed by Paul DavisPaul Davis (programmer)Paul Davis is a British software developer best known for his work on audio software for the Linux operating system, and for his role as one of the first two programmers at Amazon.com....
External links
- Apple's Audio Unit Programming Guide
- Apple's Core Audio Overview
- Apple's Audio Units trademark and license agreements
- WikiRecording's Guide to Free Audio Unit Plug ins
- Small list of free Audio Units and Tips
- A list of Freeware, Trial and Demo AU Plugins
- Tips on how to use Audio Units and which hosts that are available etc.
- Professional Audio Units plugins by Waves