What is VST ?

Steinberg's Virtual Studio Technology (VST) 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. Thousands of plugins exist, both commercial and freeware, and VST is supported by a large number of audio applications. The technology can be licensed from its creator, Steinberg.

VST plugins
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VST instruments generate audio. They are generally either virtual synthesizers or samplers. One of the first VST instruments was the Neon VSTi which was included in Steinberg's Cubase. Some, such as Native Instruments' Pro-53, specifically recreate the look and sound of famous synthesizers from years past (in this case, the Prophet-5).

VST effects, such as reverb and phaser effects, process audio input. Other monitoring effects provide visual feedback of the input signal without processing the audio. Most hosts allow multiple effects to be chained.

VST MIDI effects process MIDI messages prior to routing the MIDI data to other VST instruments or hardware devices; for example, to transpose or create arpeggios.

VST HOST
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Software

A VST host is a software application or hardware device that allows VST plugins to be loaded and controlled. The host application is responsible for handling the routing of digital audio and MIDI to and from the VST plug-ins.

There are a wide range of VST-compatible hosts available; some of the most popular include Ableton Live, Ardour, Audacity, AV Music Morpher Gold, Cubase, FL Studio, REAPER, Sonar, and Sony Acid Pro/ Music Studio. Other VST hosts include AudioMulch, Bidule, Max MSP, Kore and Renoise. There are also stand alone hosts whose sole purpose is to serve as a host for the VST plug-ins rather than as an extension of their sequencing or audio capabilities. These include Deckadance, Chainer, VSTHost and SAVIHost.

VST plugins can be hosted in incompatible environments using a translation layer, or shim. For example, FL Studio fundamentally supports only its own internal plugin architecture, but a native "wrapper" plugin exists that can, in turn, load VST plugins, among others. As another example, FXpansion offers a VST to RTAS (Real Time AudioSuite) wrapper (allowing VST plugins to be hosted in the popular Pro Tools digital audio workstation), and a VST to Audio Units wrapper (allowing VST plugins to be hosted in Apple Logic Pro Digital Audio Workstation).

Hardware

Hardware VST hosts can load special versions of VST plugins. These units are portable and usable without a computer, although all editing is done on a computer. Other hardware options include PCI/PCIe cards designed for audio processing, which take over audio processing from the computer's CPU and free up RAM. Examples of hardware VST hosts are RECEPTOR (MUSE), PLUGZILLA and V-MACHINE (SM PRO AUDIO).

Audio data can also be sent over a network using appropriate software, allowing the main host to run on one computer and VST plugins to run on peripheral computers.


VST plugin standard

The VST plugin standard is the audio plugin standard created by Steinberg to allow any third party developers to create VST plugins for use within VST host applications. VST requires separate installations for Windows/Mac/Linux. The majority of VST plugins are available for Windows due to both Apple's proprietary Audio Unit software for OS X and the lack of information and patent encumbrances that make development difficult for Linux platforms.

(Wikipedia)