Short for Software Synthesizer. A software synthesizer is a software application designed to emulate some type of hardware synthesizer. Some software programs focus their attention on emulating one specific synthesizer – often a well-known vintage model, while others have a wide range of capabilities. Some operate as stand alone applications while others function as plug-ins within some other environment. Quality varies significantly, however, as computer processing power has increases soft synths are becoming better in quality and thus more widely used, not to mention less expensive.