ORCHESTRA IN LITURGICAL MUSIC. — The Church has always been opposed to the use of musical instruments during sacred rites, despite the fact that in the early Middle Ages a rather fanciful symbolism attributed to instruments and their various parts subtle correspondences with the spiritual world, so that the seven strings of the lyre resonate with the virtues, the trumpet represents the Fourth Gospel, the skin of the drum is mortal flesh, and the ten-string psaltery adumbrates the Ten Commandments. St. Thomas Aquinas declares (Sum. Theol., 2, 2, q. 91) that instruments contribute more to distracting the soul than to concentrating II.
The notable exception made for the organ is perfectly justified, on the one hand by the character of the instrument and on the other by the restrictions imposed on its practical use (v. ORGANO). Pius X’s motu proprio on sacred music (22 Nov. 1903) leaves a door open to instrumental ensembles: “In certain particular cases, under due conditions and with fitting regard, other instruments may also be admitted, but not without special permission of the Ordinary”; and they must, like the organ, serve the singing: “simply to support and never to overwhelm” (§ 16). In § 19 it forbids the use of the piano and of the metronome, and in § 20 it grants: “only in certain special cases, with the consent of the Ordinary, may a limited, judicious, and proportionate selection of stringed instruments be permitted, provided that the composition and accompaniment to be performed be written in a grave, fitting style, altogether similar to that of the organ.” These directives were necessary to condemn usages handed down from the 18th century, for it is not singing accompanied by instruments, but the living voice that must prevail at the time; the voice of the clergy, the choristers, and the people (Apostolic Constitution Divini cultus, by Pius XI, 20 Dec. 1928; AAS, 21 [1929], pp. 33 ff.). In deference to this principle, even today in the papal chapels choral singing is never accompanied by instruments, nor even by the organ.
From all this it is easy to conclude that the orchestra in the full sense of the term, as a large ensemble, is altogether excluded from participation in divine service. On the other hand, ensembles of strings or of stringed instruments may be associated with the liturgy, including mixed ensembles, without excluding the harp, and string ensembles may be combined with the organ, always within the limits of time and in the elevated style demanded by the dignity and spirituality of sacred art.
Edoardo Carducci Agostini