Hyacinthe Eléonore Klosé was a French clarinet player, professor at the Conservatoire de Paris, and composer. Klosé is noted for his design improvements to the clarinet using the principles laid down by Theobald Boehm in his innovative work on the flute keywork. From 1839 to 1843, he enlisted the help of Louis-August Buffet of Buffet-Crampon fame, an instrument-making technician, to construct — what is known today as — the Boehm system clarinet[citation needed]. Klosé was second clarinet at the Théâtre Italien to Frédéric Berr beginning in 1836, then to Iwan Müller following Berr’s death in 1838, finally becoming solo clarinet when Müller left in 1841.