by Craig HarrisThe recorder is one of the world's oldest wind instruments. Its acoustic mechanism was already known by the cave dwellers. The instrument's lengthy tradition has been researched and preserved by Ad Libitum, a Brazilian quintet featuring soprano, treble, tenor and bass recorders, as well as piano, guitar, flute and percussion. Ad Libitum was initially conceived by Universidade Estadual do Ceare graduates Angelita Ribeiro, who plays recorder and guitar, Cecilia do Valle, who plays piano, and Rainer Beckmann, a German-born graduate of the Hogeschool voor De Kunsten Conservatory in Utrecht, Netherlands, who plays recorder. Ribeiro and Beckmann serve as the ensemble's music directors. Ad Libitum is rounded out by Cristiane Ramalho, a former student of Ribeiro, and Jaderson Teixeira, a former student of do Valle who plays recorder and percussion.