# Echo Analysis in Iberian Bullfighting Arenas Through Objective Parameters and Acoustic Simulation 1
## 3 Materials
### The Italica Amphitheatre  
The case study of the Roman amphitheatre of Italica (Figure 10) takes place as a type of precursor to the modern bullring and represents a connection to the theoretical perspective of the acoustics of performances held in the ancient buildings of theatres and circuses, studied by the authors of this work [26]. The modern conception of the circular bullring in the 18 th century retains many influences from the ancient amphitheatres: \"the arena becomes a ring\". Regarding the time of its construction, there is a general agreement of opinions that advocate the Hadrianic period, approximately between the years 117 and 138, although of unknown architect; like most Roman constructions, given the magnitude, it is thought that several architects intervened therein. Its original appearance would have been that of a great structure of opus caemeticium covered with marble slabs and stone from Tarifa. Its seating would have consisted of a podium and three caveas (ima, media, and summa), with a distribution of the amphitheatre tiers on three equal surfaces (podium and ima, media, and summa), the first two tiers of which are still in existence today. Figure 9: The bullring of Campo Pequeno: (**a**) location of sound sources (S) and receivers (R) in the ring, stalls, boxes, and grandstands; (**b**) section (Source: Plateau Colossal with permission). Likewise, in the centre of the arena is the fossa bestiaria (animal pit), originally covered by a wooden platform supported by the eight brick pillars that still remain. In Hispania, the construction of the stands often took advantage of the characteristics of the rocky hills with regard to seating. In the case of Italica, the perfect example of this type of layout is found, built between two hills upon which the stands rest, with the longitudinal axis located in the intervening valley. In this way, the building's distribution axes (E-W) are formed, which correspond to the main entrances to the arena: the Porta Triumphalis (to the east), through which the gladiatorial retinue entered; and the Porta Libitinensis (to the west), through which the victims of the combat were carried. The latter is in a better state of preservation and reveals the beginnings of the superposition of classical orders. Regarding the capacity, this is estimated to have been approximately 35,000 spectators, which supports the hypothesis that this building was designed not only for the enjoyment of the Italians themselves, but also for a military garrison that possibly existed in the city, and for the inhabitants of nearby towns. As for the use of the amphitheatre, it is known that the spectacle buildings of the most prominent cities of Hispania were in use throughout the 4 th century AD. In fact, several inscriptions found in various areas of the podium include the names of individuals whose seats were reserved: these inscriptions date back to the 4 th and 5 th centuries AD. It is therefore legitimate to affirm that this building remained in use throughout the 4 th century AD. The Italica amphitheatre is the largest of its kind built in Hispania (dimensions: 156 \(\times\) 134 m) and constitutes the largest in terms of capacity outside the Italian Peninsula. It is surpassed only by the Colosseum in Rome, the Capua amphitheatre, and the Puteoli amphitheatre (modern name, Pozzuoli). This is one of the most complex and ambitious projects of Roman architecture on the Iberian Peninsula. Figure 11 and Table 3 show the 49 source-receiver combinations used in this space. In the Roman amphitheatre of Italica, the 3 positions of the sound source and the 17 receivers took into account that its arena was designed as an oval in which the relationship between its 4 foci forms a Pythagorean triangle with a ratio of 3:4:5. Therefore, these sources were selected near the foci due to the presence of the fossa bestiaria, and to certain alignments on which the curves corresponding to the four sectors of the oval were drawn.