Image Line SimSynth
SimSynth 2.7 is a monophonic analog software synthesizer emulator. It creates sounds akin to the classic Minimoogs and Oberheim synthesizers. Like the Mini, it features a 3-oscillator design which drives a fat monophonic sound for bass, lead, and other sounds. It features a warm SVF Oberheim style filter too, overdriven by the oscillators for that authentic analog sound. And that analog sound is coming out at 16-bit, 44.1kHz stereo CD sound quality.
SimSynth 1.0 was released back in 1994. The current version, 2.7 has been integrated with FL Studio (formerly Fruityloops). SimSynth can function as a stand-alone application that generates .WAV files and/or presets that can be used in Fruityloops or any other digital audio application capable of handling .WAV files. That is, FL Studio will render and use all your SimSynth presets on the fly!
SimSynth Live is a VSTi version of SimSynth for about the same price that works in real time from within FL Studio. SimSynth Live adds some new features such as unlimited polyphony, a simple step sequencer, everything syncs to tempo, (Envelopes, LFO's, effects, etc), real time MIDI control via Phatboy and/or keyboard controllers, Reverb, a Phasor, and some decent Delay FX. Sadly, it doesn't have the drawable graphic envelopes or the sweeping filter on the delay, and there is no Macintosh support for the SimSynth.
Demos & Media
Images from FL Studio online.