To open the channel for divine energy, the senses must be quickened. Sound is a fundamental pathway for the divine. Senses of sight, smell, taste and touch are also stimulated in Vodou.
• Drumming shapes the ceremony, channeling the spirits with their special rhythmic signatures.
• The Rada ensemble, a triad of peg-tuned, goblet-shaped drums, summons the ancient spirits of Dahomey.
• The Kongo-derived, string-tuned Petwo drums, usually a pair, play the sharper rhythms of the Petwo/Kongo rites, in which the crack of a whip can also bring down the lwa.
• The gourd rattle or ason is used by the priest/priestess at key points in a ceremony. The one strung with beads or bones is used for Rada rites, the plain one for Petwo/Kongo rites.
• Priests use bells to call awaken the lwa in all kinds of private ceremonies.
• Braziers send petitions to the spirit world on a plume of smoke, and censers fill the air with scent.
http://www.amnh.org/exhibitions/vodou/tools5.html