• Profile
• Archaeoacoustics
• Publications

• Introduction
• Avebury
• Stonehenge
• Ring of Brodgar
• Stones of
  Stenness
• Maeshowe
• Dwarfie Stane
• Standing Wave Resonance
• Huntersquoy & Taversoe Tuick
• Stalled Cairns of Orkney
• Easter Aquorthies
• Grey Cairns of Camster

Ring of Brodgar

The Ring of Brodgar is a large stone circle set within a henge. It has a diameter of 100m and around 60 stones once stood there. Although fewer than half of these remain today, the monument has distinctive acoustic properties.

Similar to the Stones of Stenness nearby, echoes are the most prominent feature. In contrast to that monument, however, sounds at the Ring of Brodgar have to be loud to travel across the circle. Over such distances, sounds are also subject to influence by wind and rain. It was noted that while echoes produced by handclapping or vocalising do echo across the circle in calm weather, percussive noises generated by drums were much more effective in all the weather conditions.

The nature of echoes varied considerably in relation to both the location of the sound source and the listener. The most dramatic effect was heard when both the sound source and listener were located near to the geometric centre of the monument. Here the sound returned from all of the stones of the circle simultaneously, creating a surround-sound effect that contains the listener.

In addition, the distance travelled by the sound incurrs a delay of about one-third of a second. This means that the noise of striking a drum is followed by a brief interval of silence before returning as an echo that appears to originated from all around the circumference of the circle. The intervening distance also filters the sound so that the response sounds fuller and is more expansive. The delay between source and echo means that it is possible to create a percussive composition in which the player is accompanied by the echoes from the stones.

Away from the centre of the circle, the echo returning from the stones is staggered as the sound has to travel variable distances between the source and stones. This causes the echoes to lose coherence, suggesting that the centre might have been a focus for people. Outside the circle, the echo effect is lost completely.