The acoustic of the Catacombs of “San Gennaro” in Naples

This paper reports the results of acoustic measurements made inside the Catacombs of "San Gennaro" in Naples. The Catacombs are underground places where the early Christians were buried. The Catacombs were used until the 5th century AD, they were abandoned when the bodies of Christian martyrs were moved inside the churches built in the cities. The Catacombs were rediscovered only towards the end of the 15th century, and used as a place of prayer and religious meeting. The Catacombs of "San Gennaro" have been excavated in a rock called "tufa", over the centuries the Catacombs has not changed, and the current configuration corresponds to that the 5th century AD. In origin the Catacombs were not only places of burial, but they were also performed sacred functions, but we don't know this type of function, if they were spoken, sung or psalm. The acoustic measurements were made using the impulse response method. By the analysis of the acoustic parameters as RT, EDT, C80, D50 and STI, we tried to understand the type of religious ceremony performed