Abstract
Several studies focused on the acoustical characterisation of concert halls and opera houses analysing more or less homogeneous sets of halls and spotting reference criteria. This work presents the results of a detailed measurement campaign that was carried out over eleven small and mid-sized historical opera houses in the North of Italy with the aim of characterising this hall typology and to relate it to the reference literature. The cluster is intended to represent an adequate sample of case studies relative to different capacities and different design approaches that followed one another starting from the seventeenth century. The theatres were investigated using monaural and binaural techniques, performing impulse response measurements at each seat in the stalls and in each box. Seven ISO 3382 criteria are chosen to characterise these theatres and averaged over the three main listening areas denoted by the Italian opera house typology, i.e. the stalls, the boxes and the gallery. The correlation coefficients between interrelated criteria are presented and commented in relation to the architectural features of the theatres and to the existing literature.