Free VST Synth called “Sylva” by SynthIV.
Sylva uses three stages of Phase Modulation synthesis (Phase Mod III modulates the phase of PM II, and PM II modulates PM I, and PM I modulates the main oscillator. When a PM oscillator is off, the modulation signal will be passed to the next on in the chain). PM oscillators can have fixed, modulated, or keyboard controlled pitch (with octave and note offset). Main oscillator (at the top) runs through the envelope, which can control the amplifier and/or the filter. Envelope goes to EQ/Filter Sweep (static=eq, modulated=filter sweep), then to a stereo chorus. LFO A and B have 4 waveform choices, and LFO S uses a square wave. Note that the LFO depth will affect the offset (when depth is high, offset trends toward its center. LFO’s are tempo-synced, and can modulate the frequency of the main oscillator, PM oscillators, filter sweep, pulse width, and output volume.