The Inca Built This Three-Walled Building to Shape Sound, Study Suggests

In the remote town of Huaytará, Peru, the building that houses the Church of San Juan Bautista is more than what it seems. It was built upon a three-walled Incan structure called a carpa uasi that exchanged stability for something unexpected.

While the Incan Empire is best known for the iconic 15th-century citadel of Machu Picchu, a team of researchers is investigating the acoustic properties of the carpa uasi, another one-of-a-kind Incan construction that likely dates back to the same century. Their work emphasizes the importance of studying more than what meets the eye—literally—when tracing the footsteps of bygone civilizations.

A three-walled building

“We’re exploring the possibility that the carpa uasi may have amplified low-frequency sounds, such as drumming, with minimal reverberation,†Stella Nair, associate professor of Indigenous arts of the Americas at the University of California, Los Angeles, said in a university statement. “With this research, for the first time, we’ll be able to tell what the Incas valued sonically in this building.â€

The Inca were a pre-Hispanic civilization whose empire flourished in the 15th and early 16th centuries. When the Spanish conquistadors arrived, the Inca Empire stretched along South America’s western coast, from modern-day Ecuador to modern-day Chile.

The building in question had only three walls, potentially enabling sound, like drums, to be directed toward the opening and then beyond. Carpa uasi, meaning “tent house,†references that unique structure, and the Inca may have built it specifically to amplify sound and music

“Many people look at Inca architecture and are impressed with the stonework, but that’s just the tip of the iceberg,†Nair explained. “They were also concerned with the ephemeral, temporary and impermanent, and sound was one of those things. Sound was deeply valued and an incredibly important part of Andean and Inca architecture — so much so that the builders allowed some instability in this structure just because of its acoustic potential.â€

The importance of sound

Researchers have long known about the building, but Nair and her colleagues might be the first to recognize its potential for magnifying sound. It is the only known surviving carpa uasi and has endured the last 600 years thanks to the stabilizing force of the church built on top of it. Now, the team is working on a model to explain how sound would have spread through the carpa uasi and outside it.

“Sound studies are really critical, because we tend to emphasize the visual in how we understand the world around us, including our past,†Nair concluded. “But that’s not how we experience life—all of our senses are critical. So how we understand ourselves and our history changes if you put sound back into the conversation.â€