ARCHAEOACOUSTICS IN THE PERUVIAN HIGHLANDS

This fall features a flurry of activity involving collaboration between Stanford’s Department of Anthropology and the Center for Computer Research in Music and Acoustics (CCRMA) as an expedition travels to the Peruvian highlands to gather acoustic measurements of the mysterious underground structures at Chavín de Huántar.

The UNESCO World Heritage archaeological site, located 150 miles north of Lima in the north-central sierra of Peru, is thought to have reached the end of its monumental construction phase around 600 B.C., predating the Inca Empire and its famed Machu Picchu by over two millennia. Since 1995, Archaeology Professor John Rick has been leading Stanford teams to the site to excavate its extensive network of underground galleries. Rick’s 2001 discovery of twenty Strombus (conch) shell trumpets supports his hypothesis that the unique acoustic properties of the labyrinthine architecture were intentionally designed to facilitate a distinctive sensory experience in ancient rites. The auditory space created by the underground structures lends a disorienting sensation to the visitor and affords extraordinary acoustic properties of reverberation, reflection, and resonance. The possibility of intentional acoustic design in the Chavín architecture offers keen insight into the nature of establishing social hierarchy through sensory manipulation in pre-Inca culture.

The discovered Strombus trumpets are of particular interest as acoustic artifacts. Engravings on the shells suggest that they were brought to the site from a variety of locations. They all have similar cuts, however: the spires are precisely removed to form a mouthpiece, and a hand-sized hole underneath presumably facilitates holding the horn or perhaps varying its sound. This “Chavín cut” suggests that the instruments were prepared on site for specific ceremonial use. Strombus trumpets produce a deep resonance rich in overtones and may have produced uncanny reverberations when sounded within the Chavín galleries. Evidence implicating ingestion of hallucinogens by the ancient initiates suggests that the early rituals provided an intensely transformative experience.

Because Chavín requires conservation work that will forever alter its acoustics, the Stanford team must race to complete acoustic measurements of the space in its existing condition. Thanks to a grant from SiCa, the group will travel to Peru this September to begin comprehensive field measurements of the site before renovations occur. Armed with custom multi-microphone arrays and amplifiers, low distortion speakers, analog-to-digital converters and computer audio interfaces, the field researchers intend to complete the data-gathering phase of the project in order that mathematical analysis and generation of a computational physical model of the site may begin in the fall. The final phase of the project, to begin in 2009, will be to engineer a public interface for acoustic simulations of the ancient practice under authentic conditions.

The Stanford investigators presented an invited paper, On the Acoustics of the Underground Galleries of Ancient Chavín de Huántar, Peru, at the Acoustics’08 conference in Paris on July 3.

Chavín de Huántar Archaeological Acoustics Project Team:

John Rick, PhD, Professor, Achaeology/Anthropology
Julius O. Smith, PhD, Professor, CCRMA/EE
Jonnathan S. Abel, PhD, Consulting Professor, CCRMA
Patty Huang, MA, PhD Candidate, CCRMA
Miriam Kolar, MFA, PhD Candidate, CCRMA
John Chowning, DMA, Professor Emeritus, CCRMA/Music
Perry Cook
Jyri Huopaniemi
Cobi van Tonder
Leila Takayama