Software synthesizer
A software synthesizer or virtual instrument is a software app or plug-in that generates digital audio, usually for music. Virtual instruments can be played in real time via a MIDI controller, or may be readily interfaced with other music software such as music sequencers typically in the context of digital audio workstation (DAW) software. Virtual instruments exist for essentially every musical instrument type, emulating various types of synthesis, orchestral instruments, drums, guitars, pianos, and even recreations of specific models of hardware synthesizers and classic keyboards.
Mainstream virtual instruments were first introduced in the late 1990s, and popularized by Steinberg's introduction of VST instruments in 1999. As computer processing power increased into the early 2000s, virtual instruments could produce what previously required the dedicated hardware of a conventional synthesizer or sampler. By 2014, virtual instruments had become the second-largest music software product category in terms of revenue, with the first being DAW software.