synthv1

A really great classic subtractive synthesizer software. If you're familiar with subtractive synths, you can make a variety of sounds with it, such as leads, pads, bass, synth strings, FX, etc. It also has a nice set of built in effects to shape your sound further. It comes as both standalone as well as lv2 plugin which can be used with a DAW like Qtractor and you can automate all its parameters.