Many VSTs work standalone - that is they are started (run) and create their own window to operate in. Some do not have a standalone mode and need a host application to handle their studio hardware interfacing (Audio and MIDI) connections/signal paths.

If I intend to record my VSTs as audio instead of MIDI I may want to bring them up with as little hassle as possible so a HOST is a quicker way to get them up and running as opposed to an entire DAW/sequencer with menus to dive through.

If I am creating patches I may want to start the VST without creating a session or song file. Many of the advanced hosts have additional features that sequencers do not. They also make it very easy to layer VST patches together and treat them as one sound.

For the magazine, VST hosts provide a great way to test a plug-ins' performance if it can't be run in Standalone. If I want to push the VST until it crashes or maxes out my system it doesn't become a test of both the Plug-in and the sequencer together. Some plug-ins (the free and quirky older ones) don't always load in every sequencer.

VST = V.irtual Ins.trument T.echnology

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. 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.

With 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.

 

What is Chainer?

http://www.xlutop.com/html/chainer.html

Chainer is a multi-effect and multi-instrument rack for musicians and sound designers. It's a VST host that runs as a standalone application, VST effect and VST instrument.

Chainer allows you to stream the ASIO or VST input signal through up to 10 chains of VST effects so you can use your PC as a realtime multi-effect processor.

In addition Chainer enables you to play several VST instruments at the same time. You can layer several instruments to create complex sounds or you may play instruments on different MIDI channels: Chainer turns your PC into a multi-timbral sound generator.

To achieve very low latencies, the standalone version supports ASIO 2.0 compatible soundcards. A fast PC, a good ASIO driver and Chainer enable you to use your VST effects and instruments almost like real hardware devices.

It is possible to load up to 100 VST plugins per instance of Chainer, but since you can load Chainer in itself there is no actual limit.

The parameters of Chainer and also parameters of the loaded VST plugins can be controlled through MIDI CC messages or VST automation.

A bonus feature of Chainer is the ability to create multi-samples from your VST instruments in WAV and SF2 format for instant use in samplers.