The performing choir comprises ca. 140 8-to-25-year-old boys and men. The assembly of the choir is SSAATTBB (1st and 2nd
soprano, 1st and 2nd
alto, 1st and 2nd
tenor, 1st and 2nd
bass). After puberty, boys proceed from
boy voices to
male voices. Each voice has its own
prefect, who is the "leader" of his voice and is responsible for keeping order. The prefect is the position of trust appointed by conductor of the choir. The choir actively practices several times a week and give concerts both at home and abroad. The choir operates in connection with training groups named B-, Choral- and Cappellachoir, which prepare 7- to 12-year-old boys to perform in the main chorus (A-Choir). CM-Music Institute also runs musical kindergartens for 4-to-7-year-old boys in the
Helsinki metropolitan area. Boys may also choose to have classical singing,
piano and
flute lessons, as well as education in
music theory. ==Repertoire==