By Dan Avery and Ian Randall | DailyMail
Sound reverberated inside Stonehenge thousands of years ago, according to a new study.
Researchers in the UK used a scale model to study the acoustic qualities of the mysterious monument built some 4,000 years ago when all 157 stones were intact.
To approximate the original location and shape of the stones, laser-scanned data of Stonehenge's modern-day configuration was combined with archaeological evidence of its original layout – and the team found it was more like a movie theater than an open-air space.
It's unlikely Neolithic Britons had that in mind when they constructed Stonehenge in the 3rd millennium BC, but researchers believe they would have exploited the sound effects while singing or speaking.
‘There are clues to where the stones were, such as filled-in holes where they were stood,' acoustic engineer Trevor Cox, who led the project in collaboration with Historic England, said last fall.
Today, Stonehenge is composed of 63 stones, including five standing slabs, known as sarsen stones.
A 1:12 scale model, dubbed Stonehenge Lego, was constructed under the assumption there were originally 157 stones on the site, including 30 in the outer circle.
Researchers at the University of Salford used 3D printing to create 27 stones of different shapes and sizes.
A 1:12 scale model was constructed using 3D printing and custom modeling. Speakers placed inside and outside ‘Stonehenge Lego' emitted chirps at various frequencies
Then they used silicone molds of those stones to construct the remaining 130.
Stonehenge Lego was placed in a special acoustic chamber where it was tested via a technique called ‘auralization.'
‘It is the sound equivalent of visualization,' Cox said. ‘We can virtually place a source of sound in a space.'
Speakers at various points inside and outside the model emitted chirps that varied from low to high frequencies.
The team found mid-frequency chirps briefly lingered inside Stonehenge Lego.
Reverberation time – or how long it takes sound to degrade by 60 decibels – averaged about 0.6 seconds.
That's enough to boost voices or musical instruments, Cox said.
In comparison, reverberation time is about 0.4 seconds in a typical living room and around two seconds in a large concert venue, according to Science News.
When Cox transmitted his own voice into Stonehenge Lego, he said the acoustics gave it a ‘majestic and reverberant' quality.
Because of how the real stones were laid, he said, his voice wouldn't have projected into the surrounding countryside or even toward people standing nearby.
And sounds from outside the Wiltshire-based attraction wouldn't have reverberated inside, either.
‘Surprisingly, considering the Stonehenge has no roof and there are lots of spaces between the stones, the acoustics are more like an enclosed room, like a cinema, rather than an outdoor space,' Cox said. ‘It really does enhance singing.'
