sentences:  Haydn's concerto includes melodies in the middle and lower register, exploiting the capabilities of the new instrument.There were attempts all over Europe around the mid-classical era to expand the range of the trumpet using valves, but Weidinger's idea of drilling holes and covering them with flute-like keys was not a success as it had very poor sound quality.Thus the natural trumpet still had continual use in the classical orchestra while the keyed trumpet had barely any repertoire.