Vortices, Drumming, and Standing Waves

In the introduction to Vortices: Altered Consciousness at Newgrange and Knowth Passage Tombs, Elizabeth McCormack, MFA, MA reveals that, under the guidance of ceremonial leaders, passage tombs may have provided communities direct access to the realm of the dead. These ritual monuments provided an ideal environment to induce ecstatic trance and bridge the abyss via sound. Inside the stonebuilt chambers, sound waves form a vortex or tunnel to the spirit world. McCormack cites an ethnographic study of Chukchi shamans who used the architecture of sound itself to create unusual auditory phenomena; "it was found that in a crowded, confined room, the shaman is able to direct his voice and drum sounds to different parts of the room. The source of the sounds is lost, the song and drum shifting around the room seemingly on their own. This is accomplished through the use of standing waves. Standing waves are acoustic phenomena caused by the reflection of sound waves between solid walls, producing zones of low or high intensity of sound as waves either cancel or combine. The sound may seem to expand and move about the chamber or room. Different sounds can be heard in different parts of the room." Read more of Vortices (PDF).