This article presents aspects of the lives of the choirboys at Notre-Dame de Paris between the 14th and the 18th centuries. We evaluate the sound produced by children’s voices during liturgical celebrations based on their location inside the choir using acoustic simulations. The enclosed liturgical choir of Notre-Dame created an acoustical subspace in the cathedral with suitable acoustics for the clergy within the choir, but not for the laypeople in the nave. These simulations demonstrate that this liturgy of the Hours was meant mostly for God and the canons who sang it. In addition to testing conditions where the children sang from within the chancel with and without the jubé, we also investigate the situation where the children sang from on top of the jubé as they did for certain special occasions. While placing singers on the jubé may have had visual appeal or ceremonial importance, simulations reveal that moving the singers from the ground floor of the choir to the jubé would have actually had a negative effect on the loudness and clarity of the sound heard by the canons in the choir.