: Out of 750 participants, 22% reported a surge in "odd sensations" specifically when the 17 Hz infrasound was present. Reported Symptoms :
: Scientists from the National Physical Laboratory used a 7-meter pipe to generate the tone, playing it during specific pieces without the audience's knowledge.
The study of infrasound and anxiety often references the work of , who identified 18.9 Hz (very close to 17 Hz) as a frequency capable of causing "hauntings".
In May 2003, researchers in London conducted a mass experiment by hiding a within contemporary music during two concerts.
: This frequency is near the resonant frequency of the human eye (approx. 18 Hz), which can cause vibrating vision that creates "gray apparitions" or peripheral hallucinations.