PC users interested in making microtonal music will want to check out Xen-Arts Xenharmonic FMTS -- a free virtual synthesizer instrument plugin (Windows).

Xenharmonic FMTS is an FM synthesis VSTi with a specialized set of features. The plugin boasts a lot, considering that it's free: 4-operator FM synthesis with ring modulation, 57 operator algorithms, 11 different operator waveforms, phase and pulse-width oscillator, 22 waveforms, phase and pulse-width LFO modulation, 6 independent envelope generators, 2 state variable filters with 12 and 24 dB response, effects and a saturator, a 4-voice stereo ensemble detuner, and much more.

The new plugin's full set of features are listed below:

• Internally loads and externally receives both MTS (MIDI Tuning Standard) bulk dump and single note microtuning files
• Operator ratios can easily be set to values that are coincident with the microtuning being used, thereby producing tuning related FM sidebands in the timbre of the instrument
• Isoharmonic spacing of the operator ratios
• Precise values may be set for microtonal pitch-bends
• Arbitrary microtonal period shifting makes it possible to pitch transpose in both octave and non-octave increments
• FM-RM oscillator
• 4-Operator FM synthesis with ring modulation
• 57 Operator algorithms
• 11 Different Operator waveforms
• Phase and pulse-width oscillator
• 22 Waveforms
• Phase and pulse-width LFO modulation
• 6 Independent envelope generators dedicated to modulating Operators A-D, filters, and VCA
• Velocity sensitive
• Keyboard tracking
• 2 State variable filters with 12 and 24 dB response
• Cutoff frequencies modulated by Velocity, envelope generator, LFO, and keyboard tracking
• Low-frequency oscillators can be set to modulate the cutoff frequencies of the filters at audio rates, thereby producing sidebands in the signal
• Effects
• Saturator for subtle to extreme distortion
• 6 dB LPF warm filter
• 4-Voice stereo ensemble detuner

Now available, the Xenharmonic FMTS plugin may be downloaded for free from the Xen-Arts Web site, xen-arts.com.