The shamans of Old Europe and of the ancient Celto-Germanic tribes used sound, vibration and sound vibration interference patterns as part of their shamanic practices. Ancient megalithic monuments like Newgrange (Ireland), Stonehenge (England) and the Chambered Cairns of Orkney (Scotland) all used acoustics and sound vibration to induce altered states of consciousness.
As did the builders of the Orion Pyramids of Giza design the megalithic pyramids using the properties of sound vibration, so too did the builders of the thousands of Neolithic underground tunnels spread all throughout Europe. A massive system, from the North of Scotland down to the Mediterranean, these tunnels were constructed with stone walls possessing piezoelectric properties able to reflect standing waves of sound vibration. The presence of percussion "ringing rocks" were also features of many of the European caves containing Old Stone Age Paleolithic cave art.
Even after conversion to Christianity, Celto-Germanic cultures continued to build megalithic structures designed around sound, vibration and sound vibration interference patterns like Rosslyn Chapel in Scotland and in all of the great cathedrals throughout European culture. Shamanism never died in Europe. The shamanic spirit is integral to who we are.