Download PolyIblit:

VST Synth with advanced routing

The PolyIblit by Andreas Ersson is a free VST compatible software synthesizer. It features three virtual analogue (VA) oscillators, and a noise generator, Pulse Width/Slope Modulation, and Two LP/BP/HP filters. Further, PolyIblit has four LFO's with tempo sync, and four ADSR envelope generators, that can be triggered by Note On, LFOs, Control Change or portamento. The PolyIblit VST plugin is a very capable all-round synth equally good at producing beautiful pads and piercing leads.