The Virtual Studio Technology (VST) interface is developed by Steinberg and first launched in 1996, VST creates a full, professional studio environment on your PC or Mac. VST allows the integration of virtual effect processors and instruments into your digital audio environment. These can be software recreations of hardware effect units and instruments or new creative effect components in your VST system. All are integrated seamlessly into VST compatible host applications. These VST modules have the sound quality of the best hardware units, yet are far more flexible. All functions of a VST effect processor or instrument are directly controllable and automatable; either with a mouse or with an external hardware controller. VST also allows easy integration of external equipment, allowing you to put together a system tailor-made to your needs. Being an open standard, the possibilities offered by VST have steadily been growing over the past decade. New virtual effect processors and virtual instruments are constantly being developed by Steinberg and of course dozens of other companies. Leading third party VST instrument creators include renowned software companies such as Native Instruments, Arturia and Spectrasonic as well as known hardware manufacturers like Korg, Waldorf or Novation. Companies such as Waves, Sonnox, Antares and TC Works have contributed virtual effect processors. For more information: [Steinberg][Wikipedia].
The VST format has been brought up to version 3, though many developers still support the older VST 2.xx format. VST3 plugins are always 64-bit-compatible, offer sidechaining options and dynamically assignable outputs. However, they dispense with the popular preset/patch and bank storage format (.fxp and .fxb, respectively), which can make transferring patches between plugins and projects trickier.
There are still many 32-bit plugins. Often this isn’t an issue, as most plugin providers offer both 32-bit and 64-bit versions that can exist side-by-side on the same computer. You can’t run a 64-bit plugin in a 32-bit host; the reverse is also usually true. Some 64-bit DAWs have a built-in ‘bridge’ that can make 32-bit plugs available. If your DAW (e.g., Cubase) doesn’t, you’ll need a third-party bridge or wrapper (e.g., JBridge)
The other thing to bear in mind is that many plugins will require up to five destinations:
* The plugin file itself, that goes into your choice of vstplugins folder.
* Any 64-bit programme stuff, such as uninstall, manuals etc.
* Any 32-bit programme stuff, such as uninstall, manuals etc.
* There may be a 4th destination with the Windows /ProgramData folder where presets get stored.
* There may even be a large sample collection that you can save to a 5th destination
You can see [here] how I organized my plugins
See also: Differences between VST2 and VST3: https://www.musicianwave.com/vst2-vst3-differences/