ACOUSTICAL RESONANCES OF ASSORTED ANCIENT STRUCTURES

Rudimentary acoustical measurements performed inside six diverse ancie nt structures revealed that each sustained a strong resonance at a fre quency between 95 and 120 Hz, despite major differences in chamber sha pes and sizes. The resonant modal patterns all featured strong antinod es at the outer walls, with appropriately configured nodes and antinod es interspersed toward the central source. In some cases, interior and exterior rock drawings resembled these acoustical patterns. Since the resonance frequencies are well within the adult male voice range, one may speculate that some forms of human chanting, enhanced by the cavi ty resonance, were invoked for ritual purposes. (C) 1996 Acoustical So ciety of America.