by Trevor Cox
Salford Acoustics has created the first ever acoustic scale model of a prehistoric site. The 1:12 scale model of Stonehenge allows the acoustics from 4000 years ago to be explored. The current site has many stones missing and so doesn’t sound like it did in the past. The model uses English Heritage's laser scan dataset from 2011 and the latest archaeological evidence to properly model the layout, size and shape of the stones.
Physical scale models are a tried and tested technique in the design process of constructing concert halls, but in order to model the sound correctly, the test frequencies are required to be 12 x larger meaning the sounds produced are within the ultrasonic region. The evaluation of the measurements then follows the latest techniques from architectural acoustics.
There have been very few studies into the sounds created at Stonehenge. We know, for example, that within Stonehenge the reflections from the stones should have helped to reinforce speech. But by how much? This to-scale model, which incorporates archaeological mapping techniques to better understand the layout of the original site, will allow us to access brand new insights into what our ancestors would have heard in the stone circles.
Preliminary results show a reverberation time around 0.6 seconds, something like a medium-sized cinema. Given that Stonehenge has no roof and lots of gaps between the stones, it is surprisingly long.