"Music is among the many and great gifts of nature with which God, in Whom is the harmony of the most perfect concord and the most perfect order, has enriched men, whom He has created in His image and likeness. Together with the other liberal arts, music contributes to spiritual joy and the delight of the soul...
..Besides the organ, other instruments can be called upon to give great help in attaining the lofty purpose of sacred music, so long as they play nothing profane nothing clamorous or strident and nothing at variance with the sacred services or the dignity of the place."
(MUSICAE SACRAE ENCYCLICAL OF POPE PIUS XII ON SACRED MUSIC)
The following video demonstrates the proper implementation of "other instruments" that are relevant to a specific culture (1 min mark).