# Measurements of Acoustical Parameters in the Ancient Open-Air Theatre of Tymdaris (Sicily, Italy) +
## 6 Conclusions  
This work presents the results of an acoustical measurements campaign in the ancient open-air theatre of Tymdaris. Measurements based on ISO 3382-1 were conducted in situ in unoccupied conditions using omnidirectional sound sources and receivers. The impulse responses (IRs) were measured directly using a firecracker as the impulse source, and a dodecahedral source, which generated a sine sweep. The acoustical parameters described in the ISO 3382-1 standard, that is, Reverberation Time (\(T_{20}\)), Clarity (\(\mathrm{C_{50}}\)) and (\(\mathrm{C_{80}}\)) and Sound Strength (G), were obtained from the IRs measured at each receiver position. The following main results are highlighted.  
* For Reverberation Time (\(T_{20}\)), the measurements with the firecrackers and the dodecahedron sources returned similar results. When looking at the average value across all source types and positions in the mid-frequencies range, \(T_{20}\) was 0.57 s; this value is relatively lower if compared to similar open-air ancient theatres, which is a common trait for those sites where the scenaae from is no longer in place.
* For the Early-to-Late Energy parameters, the average theatre values in the mid-frequencies ranges are: \(\mathrm{C_{50}}=12.6\) dB and \(\mathrm{C_{80}}=17.5\) dB; yet, such figures should be interpreted with caution as due to operational constraints (open-air conditions) it was not possible to accurately assess the results in alignment with the ISO 3382-1 guidance.
* For the parameter Strength of Sound G, the values for the theatre in the mid-frequency range are typically low, going from \(-1\) to \(-8\) dB, depending on sound source type and position.  
A very good reproducibility has been shown between the measurements obtained with the two different measurement chains, with differences on average spatial values for the whole theatre that are equal to 0.01 s for \(T_{20}\), and less than 0.3 dB for \(\mathrm{C_{50}}\), \(\mathrm{C_{80}}\) and G.  
Future research should explore additional parameters that could be more suitable for the characterization of the ancient theatre, and unroofed historical spaces more broadly [49]. At other sites, the context should also be taken into account, considering the possible influence of the state of conservation of the architectural elements and materials.  
[PERSON] and [PERSON] conceived, designed the data collection campaigns and collected data on site; [PERSON] performed data analysis together with [PERSON] and [PERSON]; [PERSON], [PERSON] and [PERSON] drafted and curated the first version of the manuscript. All the authors revised the paper. All authors have read and agreed to the published version of the manuscript.  
This research was funded through a Ph.D. scholarship awarded to the first author by the Politecnico di Torino (Turin, Italy).  
The authors are grateful to [PERSON], [PERSON] and [PERSON] from the Acoustics Laboratory of Politecnico di Torino for their technical contribution to this project. The authors are grateful to [PERSON] and [PERSON] from the University of Ferrara, [PERSON] from the University of Parma and [PERSON] from KU Leuven for their suggestions and advice.  
The authors declare no conflict of interest.