The acoustics of stonehenge
A research is being undertaken to unravel the acoustic response of Stonehenge, which is the largest and most complex ancient stone circle known to mankind. Perhaps the first time acoustic effects at Stonehenge were noticed was during its first phase of construction which corresponds to the bank and ditch and the 56 Aubrey holes which are now believed to have held blue stones in them. The evidence is that a large diameter stone ring does present a discernible echo, particularly from the centre of the circle where reflections from each stone are focused. The less regular shape of stones at Stonehenge is likely to provide more scattering at midfrequencies where the irregularities correspond to wavelengths smaller than about 30cm. Clearly the acoustic response measured within the original Stonehenge is very short. The ETC shows a few early reflections within 20ms, which after simple calculations can be associated with the floor, toppled stones very near to the microphone position and the first set of standing stones in the inner circles.