57 These laws warn that great prudence and care should be used in this serious matter in order to keep out of churches polyphonic music which, because of its heavy and bombastic style, might obscure the sacred words of the liturgy by a kind of exaggeration, interfere with the conduct of the liturgical service or, finally, lower the skill and competence of the singers to the disadvantage of sacred worship.
Source: Musicae Sacrae (Vatican.va)