The Boys Choir of St. Jacob is made up of 34 members.
The Choir runs a two year choir school and rehearses three times a week
in the choir hall of The St. Jacob Community House.
Every semester new boys are approved to become members of the St. Jacob Choir School.

Just a couple of examples from websites

Mixed Choir is an auditioned mixed ensemble that meets on a daily basis. Enrollment varies between 85 and 110 voices, and is comprised of freshmen through senior boys, and mostly freshman girls. The choir performs a minimum of three concerts a year. Students are encouraged to participate in District and State Solo and Ensemble contests. Solo and group performance opportunities exist for all students. Members of the choir are used for stage construction, stage crew, make-up, lights, and sound for the annual musical presentation. These students are also an integral part of the annual Madrigal Dinner as serving wenches, beggars, recorder consort members, brass ensemble members, and various other roles. Literature is of a medium difficulty with explorations into all styles and some foreign language.