 His students included the celebrated French virtuoso bass Pol Plançon (1851–1914), whose voice is preserved on gramophone recordings made in 1902-1908.Duprez also devised a system of written exercises for singers and composed a few less than successful operettas.In his 1880 book "Souvenirs d'un chanteur", Duprez, a close friend of Donizetti's, related in deeply felt terms the bitter setbacks and obstructions which the Bergamo composer had suffered in the theatrical world.