A quick search of the archives says this is probably the most polyphonic homebrew synth we’ve seen, and listening to the sound sample on the project page, it sounds pretty good, to boot.

Popular singing has a highly valued place in Georgian culture. Polyphonic singing, in the Georgian language, is a secular tradition in a country whose language and culture have often been oppressed by ...

Traditional Albanian polyphonic music can be divided into two major stylistic groups as performed by the Ghegs of northern Albania and the Tosks and Labs living in the southern part of the country.

Elberse, Anita, Jehoshua Eliashberg, and Julian Villanueva. "Polyphonic HMI: Mixing Music and Math." Harvard Business School Case 506-009, August 2005. (Revised September 2006.) (Spanish version also ...