Well, I do not think anything needs to be commented - the author explains the things himself.
http://spk.if.uj.edu.pl/ConsciousFlesh/pspeaker/PSPEAKER_en.html
Most plasma tweeters rely on Klein ionophone. More interesting is reversible (act as microphone too) Ostroumov ionophone that unlike Klein does not produce RF noise. It uses 10kV polarisation voltage for electrodes and 100V for musical signal on the grids:
Simplest plasma tweeter: youtube.com/watch?v=26G4Gz8g90c