Infrasound: The 19 Hz Fear Frequency

This simulation renders a room cross-section as a low-frequency source drives a standing pressure wave across the floor plan — because 19 Hz has a wavelength of roughly 18 metres, comparable to ordinary room dimensions, the room's own length selects which resonant mode forms, shown as a live compression/rarefaction color field with pressure nodes and antinodes. Beside it, a schematic eyeball and resonance-response curve illustrate why 19 Hz in particular has drawn attention: engineer Vic Tandy's 1998 investigation into a reportedly haunted laboratory traced an unexplained sense of unease and a glimpsed shape to a fan producing an infrasonic tone near that frequency, which he hypothesized sits close to a resonance of the human eye. Sweep the frequency slider past 19 Hz, adjust sound pressure level and room length, and watch both the standing-wave pattern and the eye's modeled response shift together — presented as a real, researched hypothesis with one documented case behind it, not a proven universal mechanism.