Oxe FM Synth (version 1.3.1 shown above) is a touch-sensitive, realtime polyphonic FM-based music synthesizer created and maintained by Oxe Software, recently ported to the linux platform as a VST plug-in instrument.
Oxe has 6 operators (oscillators). Each operator can modulate itself and the other operators. This modulation ability is controlled in the matrix section on the righthand side of the GUI. In addition, there is "Operator X" that controls noise generation/limiting; and "Operator Z" that controls a global filter. The filter has low-pass, highpass and bandpass settings.
Each operator has 6 waveform possibilities: sine, triangle, saw, bandlimited-saw, square and bandlimited-square. Coarse frequency detuning for each operator includes a range of +/- 4 octaves and 2 semitones, fine frequency detuning with a range of +/- 01 semitone. Velocity sensitivity for each operator is available, as well as amplitude scaling (key follow).
An LFO section is included, and has waveforms identical to those of the operators. The LFO destination options are pitch, Operator X or Operator Z.
Preset management is provided at the top of the GUI, and is very clear and straightforward. Presets can be scrolled in increments of 1 or 10. 16-midi-channel control is also available. Additional delay and reverb effects are included, with specific parameter controls at the top righthand area, and global level controls at the bottom righthand section.
Some patchbanks available at KVR audio: HERE