How Archaeologists are Using GIS to Explore Sounds of the Past

Acoustic archaeology, or archaeoacoustics, is the study of how ancient populations may have experienced sound in the past as they moved through the landscape.  Two archaeologists are using GIS tools to model the ancient soundscape of New Mexico’s Chaco Canyon.  There, Anasazi, or Ancestral Puebloan lived in the area more than a thousand years ago around 850-1150 CE.

The researchers wanted to understand the relationship between the built environment of Chaco and its soundscapes.  To do this, they developed the Soundshed Analysis Tool using ArcGIS.  This GIS tool models the geographic spread of sounds such as human voice and musical instruments. As a society that practiced oration, the researchers wanted to understand the geographic extent to which speakers would be heard.  In addition, the Chacoan incorporated musical elements to their rituals and performances as evidenced by recovered instruments such as bone flutes and whistles, wooden planks (i.e., “foot drums”), copper bells, and conch shell trumpets.

Scripted using Python, the tool uses seven input environmental and cultural variables: the sound source height, frequency of the sound source, sound pressure level of the source, the measurement distance from the source, air temperature, relative humidity, and the ambient sound pressure level of the study location.  Additional inputs include the site location and elevation data from LiDAR.  The Soundshed tool then outputs a viewshed of the sound which the researchers have termed a soundshed.  The tool is adapted from SPreAD-GIS which was developed to model the propagation of engine noises across forests.

Soundshed of an elite orator speaking at 84 dB(A) with a peak long-term average frequency of 325 Hz. Source: Witt & Primeau, 2019

Soundshed of an elite orator speaking at 84 dB(A) with a peak long-term average frequency of 325 Hz. Source: Witt & Primeau, 2019

The Study

Witt, D., & Primeau, K. (2019, June). Performance Space, Political Theater, and Audibility in Downtown Chaco. In Acoustics (Vol. 1, No. 1, pp. 78-91). Multidisciplinary Digital Publishing Institute.

Related

Primeau, K. E., & Witt, D. E. (2018). Soundscapes in the past: Investigating sound at the landscape level. Journal of Archaeological Science: Reports, 19, 875-885.

Soundscapes in the past: Adding a new dimension to our archaeological picture of ancient cultures.  (2017, August) The Conversation


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