VST is the "overall" name of the technology; VSTi is to differentiate VST instruments from VST effects (although confusingly there isn't really an equivalent abbreviation for effects - I guess "VSTe" would make sense...).
VST is the "overall" name of the technology; VSTi is to differentiate VST instruments from VST effects (although confusingly there isn't really an equivalent abbreviation for effects - I guess "VSTe" would make sense...).
VSTi - Virtual Studio Technology instrument - a sound patch or sampler/rompler
VST (or VSTfx) - Virtual Studio Technology fx - reverb/delay/phaser/distortion/bitcrusher/etc
VST was a creation of the folks at Steinberg to integrate other devices into their flagship products Cubase and Nuendo. It allowed them as well as 3rd parties to develop effect and synthesis technologies that weren't tied to the core audio engine but could still be rendered by it at the end of the day.
Unlike a lot of technologies, they made it open so that anyone can develop/create their own VSTi or VSTfx. There isn't even a need to register as a developer unlike some other companies, as you can find 3rd party development platforms (such as synthedit) that aid in your development activities
Are VST and VSTi merely two different ways of referring to VST plugins based on whether they're used for effects or for instruments, or are they actually two different specs? I.e. does one use functions/parameters/classes/whatever that the other doesn't? I haven't been able to find any specs on VSTi specifically..