Enigmacoustics' electrostatic super-tweeter
The Sopranino's instruction manual shows that it is wired in parallel with the main speaker's terminals and is intended to sit on its top surface. A rear-panel switch allows the owner to change the crossover frequency to either 8, 10, or 12kHz, each having 2nd-order slopes. The manual does mention that the tweeter's dispersion narrows with each increasing crossover frequency selection. Frequency response was specified to be 8kHz to 40kHz, +/- 3 dB.
The promotional brochure describes the development of a method to "permanently implant charges on a non-conductive film (called a "NanoFilm") with special molecular structure serving as a charge holder." The two add-on supertweeters are sold in a luxuriously padded, elegant peach wood box). Unfortunately I was not able to hear the demonstration, but my interest was certainly piqued by the technology promised. How such an add-on tweeter might perform when causally added to another loudspeaker would also be of interest.