In the 9th century, Chacoan community leaders used trumpets made from conch shells to gather the local community. The shells, gathered from over 1,000 km away, were likely audible to almost all members in a community. In fact, Chacoans might have constructed their communities around being able to hear this sound.
The soundscape of a conch-shell trumpet around a community area. For comparison, a whisper is about 30 dB, normal conversation is about 60 dB. Image credits: Van Dyke et al, 2024.
Ancient soundscapes
Between AD 900 and 1150, Chaco Canyon in New Mexico was a flourishing cultural center for Ancestral Puebloans. This area was the heart of a vast network of communities that built imposing houses and stone monuments. The communities were highly organized, with sophisticated road systems connecting them, suggesting a complex societal structure with extensive trade and communication.
“Chaco Canyon is surrounded by over one hundred understudied great house communities”, says lead author Professor Ruth Van Dyke from Binghamton University. “We sought to determine if extra-canyon great house communities demonstrated relationships similar to Chaco Canyon between landscape, community layout, and sound.”
However, some things about these cultures are unclear. Take, for instance, the conch shells.
Conch-shell trumpets have been found in several communities around Chaco Canyon. Today, they still play a role in some ritual practices — even though the nearest source of shells is around 1000 km away. So, they must have been important to be gathered so far away. But how where the trumpets used?
The ruins of Chetro Ketl in Chaco Canyon (New Mexico, United States). Image credits: NPS.
To get to the bottom of this, researchers digitally modelled the sound of a conch-shell trumpet in relation to other features in the landscape. They calculated how far some sounds can travel in the environment and how loudly they would be heard in various locations.
These resulting “soundscapes” show that playing the trumpets from strategic places could have been heard from all around the community
“This is not unlike the idea of a medieval church bell calling a community to mass”, states Professor Van Dyke.
The soundscape of a conch-shell trumpet around a community area. Even in scattered communities, most houses would have been able to hear a call. Image credits: Van Dyke et al, 2024.
Sonic “footprints”
Archaeology is often a very visual science. Researchers find things and they analyze them — visually. But, in this study, the team focused on sounds.
The concept of ‘soundscapes’ — the sonic environment consisting of both natural and human sounds — offers valuable insights into Chacoan life. The study utilized Geographic Information System (GIS) modeling to map the reach of sounds emitted from great houses, revealing an overlap with community habitation sites.
This suggests that being within hearing distance was likely a consideration in settlement planning, akin to modern-day zoning practices based on noise levels or visibility.
The Chacoan buildings also appear strategically positioned within earshot of each other. Researchers believe that the audible range of conch-shell trumpets played from these buildings could have reinforced community ties. The sound would act as an invisible thread connecting individuals across the landscape. Simply put, the conch trumpets would have served as a rallying call for the community, though the purpose is not entirely clear.
“Soundscapes were meaningful dimensions of past experiences, landscapes, and environments and are important facets of social interaction in the ancient world,” observes Professor Van Dyke. “Management of archaeological and heritage sites should incorporate consideration of the auditory environment.”
Designed around sounds?
Another example of scattered houses being in the acoustic (and visual) range of the conch trumpets. Image credits: Van Dyke et al, 2024.
The team modelled the sounds in five communities. In all of them, the acoustic reach was impressive.
Bis sa’ani: Sound from trumpets at this site reached approximately 62.5% of nearby habitations, constrained by natural landforms that blocked the sound in certain directions.
Kin Klizhin: Here, the reach was even more extensive with about 69.6% coverage, emphasizing the role of sound in daily communications and gatherings.
Morris 40 and Padilla Wash: Both sites showed significant coverage, despite physical barriers like hills and ridges shaping the soundscape.
Pierre’s: Demonstrated a sophisticated use of landscape to maximize auditory connection, with sound reaching most of the community’s living spaces.
The soundscape is so impressive that researchers are actually wondering whether the communities were shaped around the environment’s acoustics. If this is the case, sound would have played an important role in maintaining social structures within Chacoan culture. The ability to hear announcements or ceremonies from communal leaders could have reinforced a sense of belonging and compliance with community norms.
This is all a bit speculative but, nevertheless, it’s an exciting direction for archeological research. The study of ancient soundscapes invites us to listen to the echoes of the past, providing a fuller, richer understanding of ancient lives and communities. The sonic footprints left by the Chacoan people tell us more than just where they built their homes; they suggest a society deeply attuned to its landscape, using sound as a tool for cohesion and control.
“Our study of soundscapes in Chacoan great-house communities allows a tantalising glimpse into community cohesion. Our research suggests that, like the reach of the sound of a church bell in medieval times, the sound of a conch-shell trumpet may have been one element binding Chacoan communities together.”
