White Noise Audio Software have released Additive Synth v1.0, available to buy as a Windows VSTi for $99 USD. A demo version, manual and MP3 audio demos are also available.

Features:

• 2 Spectral Oscillators.
• 128 partials per oscillator.
• Each oscillator has 128 "time frames" to allow sounds to evolve and change over time.
• FM capabilities.
• Ringmod, compression, reverb, distortion and chorus/delay.
• 2 Envelopes which can modify any parameter.
• 2 LFOs with multiple wave shapes, including arp patterns.
• Unison effects to phatten up any sound.
• 128 Band formant filter or noise spectrum.
• Can act as a 128 band vocoder.
• Formant filter has 128 time frames to allow changes over time.
• Formant Bias parameter also allows formant filter sweeps similar to sweeping the cutoff on an analog synth.
• Flexible mod section.
• On screen XY-Pad allows you to modulate parameters easily.
• Packaged with 128 presets plus dozens of waveforms and filters to make your own sounds with or create your own.
• Visually draw your own waveforms and spectral changes, similar to products like MetaSynth and Coagula.
• Draw your own filters.
• Captures the unique and sought after sound of the Kawai K5000.
• A programmers heaven, this synth will let you create nearly any time of synthesized sound.