Aaron Watson Archaeology Research
Stalled Cairns of Orkney
Stalled cairns share many architectural features with passage graves, but are distinguished by the division of their chambers into a series of stalls. Well-known examples in Orkney include Midhowe and the Knowe of Yarso.
Unfortunately, no stalled tombs are sufficiently well preserved to permit acoustic tests at the monuments themselves. While the chambers and the upright stall slabs are often intact, their roofs are either missing or reconstructed using modern materials. For this reason, the acoustic interpretation of these monuments remains speculative.
The acoustics of some stalled cairns are likely to have been distinctive. Very large examples such as Midhowe have elongated chambers with many internal divisions. The broad stone slabs that separate each stall acted as a filter, modifying the passage of sound waves. For a listener outside the entrance, this means that sounds are likely to have been progressively more distorted with distance into the chamber. Likewise, sounds generated outside the tomb will be increasingly filtered as they permeate the interior. It is interesting, therefore, that the deepest stalls were sometimes a focus for deposition. Examples include Blackhammer and the Knowe of Yarso.
At Midhowe it is possible that the sounds of the sea constituted an integral aspect of the acoustics. Located near to the shoreline, the sound of waves rolling in from the Atlantic can be loud and contain a high proportion of bass frequencies. These sounds are more likely to be heard within the monument after the higher frequencies have been filtered out by the mass of stone. Even within the modern building that houses Midhowe, the roar of the sea often constitutes a continuous background noise.