75 Great care must be taken that those who are preparing for the reception of sacred orders in your seminaries and in missionary or religious houses of study are properly instructed in the doctrine and use of sacred music and Gregorian chant according to the mind of the Church by teachers who are experts in this field, who esteem the traditional customs and teachings and who are entirely obedient to the precepts and norms of the Holy See.
Source: Musicae Sacrae (Vatican.va)