Sampleson has released Akoustic, a synthesizer based on spectral models from acoustic instruments.
This is what they say:
"Create totally new organic sounds: Akoustic is fully based on spectral modeling. Recreating organic sounds by additive and spectral synthesis. No samples are needed. We just included the spectrum DNA for each instrument (see them here). This allows to edit elements that makes timbres recognizable and unique (harmonic and inharmonic partials)."
Akoustic is designed to give a user a precise way to create new sounds, allowing them to tweak every partial in a detailed way. Envelope, tuning, offset or gain for any partial are accessible individually.
If you are looking for resonance knobs, cut-off filters and regular subtractive synth stuff, Sampleson thinks Akoustic is not for you. Akoustic will allow the user to touch details of a sound, from partials envelope, tuning and gain, to offsets and micro tuning to create unique and organic-like sounds.
Intro Price: $39 (Reg. $69). Plugin and Standalone versions included.