Mac users interested in Microtonal synthesizer generally download:
Max Magic Microtuner software is a musical scale and tuning editor/librarian for Mac OS X: it allows you to edit and play microtonal scales and it is compatible with synthesizers supporting the Midi Tuning Standard and other formats, including Max/MSP.
Additional suggestions for Microtonal synthesizer by our robot:
Eight-voice standalone is a MIDI synthesizer with built-in effects.
synthesizer with built-in effects, microtonal...hybrid synthesizer engine
An endless, polyphonic drone synthesizer.
polyphonic drone synthesizer...pass filters, microtonal tuning
Sonic Charge µTonic (pronounced "MicroTonic") is a VST / AU plug-in.
µTonic (pronounced "MicroTonic")...and percussion synthesizer combined
The Dolet for Finale software is a plug-in for the Finale music notation program that reads and writes MusicXML 3.0 and Open Score Format files....
text, better microtonal accidental support
Express yourself with the emotions of a natural string instrument sound.
and even microtonal music