DIVE IN AUDIO ENGINEERING
Audio Plugin Formats Explained — VST, AU, AAX …
Descend in the various audio plugin formats used in Audio Engineering DSP applications.
An audio plug-in is a piece of software plugin that can add or enhance audio-related functionality in a computer program known as DAW.
— Wikipedia
Well, there are many different kinds of audio plugins out there depending upon the DAW, or OS platform you might be using. The main Audio plug-in formats widely used are:
- VST (Virtual Studio Technology)
- VST3 (Virtual Studio Technology V3)
- AU (Audio Units)
- AAX (Avid Audio eXtension)
- RTAS (Real Time Audio Suite)
- TDM (Time Division Multiplexing)
DAW Native
Audio plugins typically run in an Digital Audio Workstation (DAW), which is the host software. There are many DAWs on the market, a few examples of which are: Cubase, Ableton Live, Pro Tools, Studio One, Logic, FL Studio, Garage Band, Reaper, etc. These Audio Plugin formats are associated with different DAWs in the market as:
Platform Native
Windows:
This primarily includes VST/VST3, but also can include AAX/RTAS plugins which are used in Pro Tools software.
MacOS:
This includes Audio Units (AU), VST/VST3 and AAX/RTAS. The AU is the main plugin format used by Apple systems and developed specifically for apple platforms.
Formats Explained
VST (Virtual Studio Technology)
Introduced by Steinberg in 1996 in Cubase ver. 3.02. It is the most known interface type for effects and instruments. As of today VST has evolved into its 3rd version and is commonly referred to as VST3. VST is the most widely implemented format in the industry and is supported by DAWs such as Ableton, Cubase, Sonar and more.
– Available for Windows and Mac
AU (AudioUnits)
Apple’s proprietary audio technology, part of the Core Audio provided by MacOS X. 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 utilizes Audio Unit format plugins, but other DAWs such as Ableton can also use these.
AAX (Avid Audio eXtension)
AAX is a unified plugin format which comes in 2 variations: AAX DSP, AAX Native. It was introduced as Avid created a 64-bit version of Pro Tools, and this meant that a plugin format with 64-bit processing was required. With AAX, you can share sessions between DSP-accelerated Pro Tools systems and native-based Pro Tools systems and continue using the same plug-ins.
RTAS (Real-Time Audio Suite)
The RTAS plugin format was implemented in the Pro Tools series by Digidesign up to Pro Tools 10. Many plugin manufacturers developed RTAS versions of their plugins for the sake of compatibility with the Pro Tools series of DAWs. RTAS plugins can only be used within Pro Tools (up to version 10 only).
TDM (Time Division Multiplexing)
A version of Pro Tools plugins which are installed on outboard hardware such as dedicated DSP Processors for ultra-high precision and quality. TDM Plugins are usually installed in high-quality studio setups equipped with dedicated chips that process the audio signal — as opposed to having all processing done by the computer’s CPU.
