This section is from "The American Cyclopaedia", by George Ripley And Charles A. Dana. Also available from Amazon: The New American Cyclopędia. 16 volumes complete..
Asaph, a Levite, appointed by David as leading chorister in the musical services which he organized in connection with divine worship. The duty thus assigned him descended by a certain succession in his family, constituting them a kind of order parallel with the priesthood, though not equal to them in dignity or influence. The "children of Asaph" appear still in the times of Ezra and Nehemiah as holy singers. Asaph is called in Chronicles a seer (hozeh), and twelve psalms (1. and lxxiii.-lxxxiii.) are attributed to him. Another Asaph was chancellor of King Hezekiah.