20-minute solos for amplified 1-7 harpsichords and tapes for 1-51 amplified machines to be used in whole or in part in any combination with or without interruptions". In the B'Rock version of this spectacular work Cage's soundscape is combined with the movie "Technocalyps" of the Belgian director Frank Theys and amplified with the mobile-tunes of the public.

The actual occasion for writing this serenata – a genre that wavers between cantata and opera – is shrouded in mystery. Although it was probably first performed in Italy, it is unmistakably an ode to the French king Louis XV.