Virtual Studio Technology

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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.


[edit] Overview

VST plugins are generally run within a Digital Audio Workstation, providing the host application with additional functionality. Most VST plugins can be classified as either instruments (VSTi) or effects, although other categories exist. VST plugins generally provide a custom GUI, displaying controls similar to the physical switches and knobs on audio hardware. Some (often older) plugins rely on the host application for their UI.

VST instruments include software emulations of well-known hardware synthesizer devices and samplers, emulating the look of the original equipment and its sonic characteristics. This enables VSTi users to use virtual versions of devices that may be otherwise difficult to obtain.

VST instruments require notes to be sent via MIDI in order to output audio, while effect plugins process audio data (some rare effect plugins do require a MIDI input too though, for example they might use MIDI sync to sweep the effect in sync with the tempo). MIDI messages can often also be used to control parameters of both instrument and effect plugins. Most host applications allow the audio output from one VST to be routed to the audio input of another VST (known as chaining). For example, output of a VST synthesizer can be sent to a VST reverb effect for further processing.

Appropriate hardware and drivers, such as a sound card that supports ASIO, VST plugins can be used in real-time. ASIO bypasses Windows' slower audio engine, offering much lower latency.

[edit] VST plugins

VST instruments generate audio. They are generally either virtual synthesizers or samplers. One of the first VST instruments was the Neon VSTi (see SCREENSHOT), 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.

[edit] VST hosts

[edit] 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 plugins.

There are a wide range of VST-compatible hosts available; some of the most popular include Ableton Live, Ardour, Cubase, FL Studio, REAPER and Sonar. Savihost is a stand-alone executable that runs a single VST instrument. Other VST hosts include:

VST plugins can be hosted in incompatible environments using a translation layer, or shim. For 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).

[edit] Hardware

Hardware VST hosts (e.g. Muse Receptor and SM Pro Audio's V-Machines) 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.

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.

[edit] 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.

[edit] Competing technologies

* Steinberg decided to drop support for DirectX from Cubase 4.

[edit] Programming languages

Steinberg's VST SDK is a set of C++ classes based around an underlying C API. The SDK can be downloaded from their website.

There are several ports available, such as a Delphi version by Frederic Vanmol, a JAVA version from the jVSTwRapper project at, and a .NET version - Noise. Another .NET implementation is VST.NET. This open source project also includes a framework which makes creating VST plugins easier and result in more structured code.

In addition, Steinberg have developed the VST GUI, which is another set of C++ classes, which can be used to build a graphical interface. There are classes for buttons, sliders and displays etc. Note that these are low level C++ classes and the look and feel still have to be created by the plugin manufacturer.

[edit] See also

[edit] External links

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