Citation: Amadasi, G.; Bevilacqua, A.; Iannace, G.; Trematerra, A. The Acoustic Characteristics of Hellenistic Morgantina Theatre in Modern Use. Acoustics 2023, 5, 870–881. https://doi.org/10.3390/ acoustics5030050 Academic Editor: Francesco Aletta Received: 1 August 2023 Revised: 9 September 2023 Accepted: 11 September 2023 Published: 15 September 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). acoustics Article The Acoustic Characteristics of Hellenistic Morgantina Theatre in Modern Use Giovanni Amadasi 1 , Antonella Bevilacqua 2 , Gino Iannace 3, * and Amelia Trematerra 3 1 SCS-ControlSys—Vibro-Acoustic, 35011 Padova, Italy; g.m.amadasi@scs-controlsys.com 2 Department of Industrial Engineering, University of Parma, 43124 Parma, Italy; antonella.bevilacqua@unipr.it 3 Department of Architecture and Industrial Design, University of Campania “Luigi Vanvitelli”, 81031 Aversa, Italy; liatrematerra@libero.it * Correspondence: gino.iannace@unicampania.it Abstract: Thousands of theatres were built during the Hellenistic period in Greece and overseas colonies. The main elements of the Hellenistic theatre are the following: the orchestra, where music and songs were performed to accompany the acting performance, and the koilon, where the audience sat. Hellenistic theatres were built without any ceiling, with an open-air configuration. This paper reports the acoustic characteristics of the Greek (Hellenistic) theatre located in Morgantina (Sicily, Italy) based on the technical data gathered in different listening positions selected across the sitting area (koilon). The theatre of Morgantina was built in the third century BC and renovated a few decades ago. Nowadays, it is the center of important social and cultural activities. The outcomes of the beamforming technique employed for the survey have been discussed in comparison with traditional acoustic parameters, such as ISO 3382. The scope of this article is to assess the usability of this theatre intended to be used for different types of artistic performances. Keywords: Greek theatres; Sicily; acoustics; beamforming; acoustic measurements; ancient theatres; Morgantina 1. Introduction The first theatres built in ancient Greece were located on the slope of a hill and had a structure with linear steps [1,2]. The Greek theatre is tragedy’s place of origin, as testified by the scenes drawn on many vases discovered and preserved in museums. The theatrical performances were accompanied by music, rhythm, and coral dance. Over time, the theatres were transformed into a concentric and geometrical stepped structure to improve the view for all the spectators and to distribute the sound over the audience more uniformly. Nowadays, the reconstruction of these ancient theatres is not very faithful compared to the original shapes because many theatres have been recreated by analogy and comparison with other theatres built in the same period. Due to this methodology, the reconstruction has not always preserved the original geometry and materiality, producing a significant impact on the acoustic response of these places [3]. Vitruvius, in the first century BC, described in the treatise De Architectura some general rules to respect the harmony of constructions developed by the Romans; the fundamental principles for achieving correct visual and listening conditions in an ancient theatre are introduced in Book V [4,5] of his manuscript. The rules written by Vitruvius regard the alignment of steps for both acoustic and visual purposes and the installation of vases (ekeia) under the marble seats for acoustic correction. According to Vitruvius, the vessels were made of bronze, but in some cities of the Magna Grecia in Southern Italy, terracotta vessels have been found [6]. Some of these general principles are considered for modern applications, like the use of resonators for the acoustic correction of rooms. Acoustics 2023, 5, 870–881. https://doi.org/10.3390/acoustics5030050 https://www.mdpi.com/journal/acoustics