30.09.20

Monumental acoustics: Stonehenge would have amplified sounds made within stone circle

Stonehenge model with Trevor cox measuring sound
Professor Trevor Cox with 1:12 Acoustic Scale Model of Stonehenge at Acoustics Research Centre, University of Salford. Photos by Andrew Brooks.

Acoustic modelling of Stonehenge by University of Salford academics has revealed that the prehistoric monument would have amplified sound within its circle of stones.

It is hoped the research by the UK university’s Acoustics Research Centre will lead to better understanding of why Stonehenge was built and what it was used for. 

To deliver the findings, a model of Stonehenge, one twelfth the size of the original structure, was built to see how its original 157 stones would have altered how musical sounds and speech were heard. 

The study concluded that reflections from the stones would have enhanced sounds made within the circle, making voice projection easier. The additional effect would be that those outside the circle would have been somewhat cut off from proceedings within it. 

Professor Trevor Cox, University of Salford, who is leading the project said: “Constructing and testing the model was very time consuming, a labour of love, but it has given the most accurate insight into the prehistoric acoustics to date. With so many stones missing or displaced, the modern acoustic of Stonehenge is very different to that in prehistory.”

A CAD model from Historic England was used to create the acoustic scale model, which copies a technique honed in concert hall design. The test frequencies have to be 12 times larger so the sounds are produced within the ultrasonic region. Measurements were then analysed using architectural acoustics approaches. 

Despite the discovery, researchers say it’s unlikely that the stones would have been positioned with acoustics as the sole or even primary driver with astrological alignments and aesthetic arrangement both probably playing a more important role. 

However, Susan Greaney, senior properties historian for English Heritage, who contributed to the project said: “Testing the acoustics of a scale model of Stonehenge has given some new insights into how the monument might have been used in prehistory. The results show that music, voices or percussion sounds made at the monument could only really be heard by those standing within the stone circle, suggesting that any rituals that took place there were intimate events. It’s exciting to see how modern techniques of laser scanning, 3D printing and acoustic modelling can tell us about the distant past.”

You can view the research paper here.