 His system featured two valves; the first lowered the instrument's fundamental pitch by a tone, the second by a semitone The trumpet has 45 notes by the way there are sharps and flats on all the trumpet Depressing both at once lowered the fundamental by a tone and a half.By 1814 he had developed a playable valve horn, able to play a chromatic series in the instrument's upper register.Stölzel reportedly wrote directly to King Friedrich Wilhelm III of Prussia to publicise his invention, and musical director Gottlob Benedikt Bierey of the Beslau City Theatre wrote in the "Allgemeine musikalische Zeitung" on 3 May 1815