Acoustic analysis on alternative use of <i>stadia</i> : from circus maximum of Rome and Hippodrome of Constantinople to San Siro Stadium in Milan

Ancient stadia and circus were considered by Romans the excellent places for live events. Among all of them, the most acclaimed were the horse races conducted with chariots, and this was the main sport of ancient Roman stadia or circuses. This paper deals with the digital reconstruction of two ancient stadia having similar shapes (i.e. Circus Maximum and Hippodrome of Constantinople). The digital models have been rebuilt based on historical resources and archaeological discoveries to conduct the acoustic simulations and understanding the acoustic behaviour within these places. A brief comparison with modern stadia has been carried out from an architectural perspective, as well as in terms of natural and amplified acoustics, with particular focus on San Siro Stadium in Milan, which will host the 25th Winter Olympic Games in 2026. The simulations at San Siro Stadium highlight the crucial role of the amplified audio system in enhancing music quality during live venues, ensuring a more uniform distribution of acoustic parameters across the seating areas.