Sound resonance in ancient caves and stone circles
Researchers have found that the most heavily decorated sections of Paleolithic caves — where paintings cluster — often coincide with acoustic "sweet spots": locations with strong resonance, echo, or standing-wave effects. Stonehenge has been shown to have specific acoustic properties that would create constructive interference for drums and chanting inside the ring. Newgrange passage tomb amplifies sound at its chamber resonant frequency (~110 Hz), likely deliberately exploited for ritual. Acoustic archaeology uses portable loudspeakers and impulse-response measurements to reconstruct how ancient spaces sounded.