Caratterizzazione acustica del Teatro Aveirense, Portogallo. Acustica per una sala polifunzionale di interesse storico-culturale.

This study proposes an acoustic characterization of the Teatro Aveirense, a historic performance venue located in Aveiro, Portugal. The main objective is to evaluate the acoustic behaviour of the main auditorium through in situ measurements and to assess its suitability for different types of performances, with particular emphasis on speech and music-related events. The methodological framework is based on room acoustics theory and standardized measurement procedures. Objective acoustic parameters will be determined using DIRAC software in combination with calibrated laboratory hardware. The parameters to be investigated include Reverberation Time (RT), Clarity (C80), Definition (D50), Speech Transmission Index (STI), Central Time (TS), Bass Ratio (BR), and background noise levels. Measurements will be carried out within the auditorium using multiple source and receiver positions to ensure adequate spatial sampling of the sound field. With the auditorium unoccupied, an acoustic characterization will be performed under different operating conditions, including with and without the HVAC system in operation. The results obtained include the following: • Equivalent background noise level (LAeq), with/without HVAC: 36.9 / 27.7 dB; • Noise Criterion (NC) and Noise Rating (NR), with/without HVAC: NC = 29 / 21 and NR = 31 / 24; • Average Reverberation Time (RT) [500, 1000 Hz], with 0% and 100% occupancy: 1.30 / 1.21 s; • Speech Transmission Index (STI), maximum, average, and minimum values with/without HVAC: 0.61 / 0.59, 0.56 / 0.56, and 0.53 / 0.53; • Average Clarity (C80) [500, 1000 Hz] (HVAC OFF): 2.9 dB; • Average Definition (D50) [500, 1000 Hz] (HVAC OFF): 0.53; • Average Central Time (TS) [500, 1000 Hz] (HVAC OFF): 85 ms; • Bass Ratio (BR) (HVAC OFF): 1.00. These results will allow an assessment of whether the Teatro Aveirense is more suitable for speech-oriented events, such as theatre performances and conferences, or for music performances, particularly symphonic repertoire. The collected data will also be compared with measurements previously obtained in theatres of similar architectural typology, allowing a contextualized assessment of the acoustic performance of the Teatro Aveirense within a broader reference framework. This work contributes to the systematic acoustic documentation of historic theatres and provides a technical basis for potential future optimization and acoustic enhancement strategies.