A cache of 20 Strombus shell trumpets was excavated in 2001 from an underground gallery at Chavín de Huántar, the type site of the Peruvian Early Horizon period (ca. 1200 to 400 B.C.). Strombus shell usage stretches from antiquity to present day Peru, with the trumpet function showing remarkable continuity. Soon after their discovery, a dozen of the ancient shells were played to an enthusiastic audience at Lima’s National Museum of Archaeology, Anthropology and History. Evidence suggests that Strombus trumpets are, and were, used as ritual instruments for the legitimization of political and religious power. Those uses may have developed from earlier practical uses for ritual and communication. This paper describes measured acoustical properties of a Strombus horn. Strombus blasts are rich in overtones. Source strengths as high as 111 dBA @ 1 M were observed. These high source levels support speculation that shell trumpets could have been used for signaling over great distances. The trumpets can produce strong combination tones, which, accompanied by likely ingestion of local hallucinogenic substances, the use of reflected light, and other sound manipulation, suggests that early leaders in Chavín were using a range of methods to help establish early religious and political authority.