Ħal Saflieni Temple Resonance

The Ħal Saflieni Hypogeum in Malta (c. 3600–2500 BCE) is the only known prehistoric underground temple. Its Oracle Chamber exhibits a resonant peak at approximately 110 Hz — documented by archaeoacoustician Iegor Reznikoff and later measured by Cook, Ezra and Shearer (2008), who also recorded EEG shifts in subjects, specifically a shift from left to right prefrontal dominance associated with altered states and heightened receptivity.

The full resonant band is 90–120 Hz. Sweeping through this band approximates the effect of a voice or instrument being moved through the chamber — each sub-frequency excites different standing wave nodes in the limestone walls. 110 Hz is the peak but not the whole experience.

The binaural beat adds a second oscillator offset by the specified Hz, creating a perceived pulse in the difference frequency — 4 Hz corresponds to theta brainwaves (deep relaxation, meditation).