Aspendos contains the best preserved Roman theatre in the world, and its acoustic properties have been formally measured and documented. A whisper spoken at the centre of the orchestra is audible at the uppermost tier, 60 metres away, without any amplification. Research by acoustic engineer Nico Declercq has established that Aspendos is a measurable outlier among ancient theatres, achieving sound distribution uniformity that modern concert hall design targets but rarely surpasses. The result depends on four architectural elements calibrated simultaneously: the semicircular cavea geometry, the stage building profile, the seating rake angle, and the reflector cornice. All four must be correct for the acoustic result to hold.
Aerial / satellite view of Aspendos, Antalya, Turkey