There is a need for a more accurate laboratory measurement method to predict auditorium seat absorption. The traditional method tends to overpredict the absorption of the exposed front and sides of seating blocks. An alternative reverberation chamber method was studied that involves the use of barriers to obtain realistic measurements of front and side absorption. This method was validated by comparing measurements of seats made in a reverberation chamber with in situ absorption data for the same seats, calculated from reverberation time measurements in ten auditoria with and without the seats present. The accuracy of the alternative method was satisfactory in all cases, although a severe lack of diffusion in two of the halls hindered the validation process. It was found that using a frequency-constant edge correction strip to account for side and front absorption could lead to significant errors in auditorium absorption prediction.

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A research project has been carried out by the University of Cambridge (UK), Arup Acoustics (Cambridge, UK) and the Fondazione Scuola di San Giorgio-CNR (Venice, Italy) with the purpose of investigating the relationship between music and the architectural spaces within which it was performed in the context of Venetian vocal polyphony during the 16th century. The most representative churches (San Marco, Parish churches, hospitals and monasteries) were selected for this study and the music was performed within them by the Choir of St John's College of Cambridge University. Members of the audience completed questionnaires assessing the acoustic qualities of the spaces. The results of the audience and expert scores were then statistically analyzed and correlated with a set of room acoustic indices which had been measured in the same locations. In the present paper technical aspects of the experiments and the data analysis will be illustrated. The principal conclusions were as follows: 1. There is a strong correlation between the subjective impression of reverberance with EDT and T30 and musical clarity with C80; 2. A grouping of the churches by typology was found by analysing the reverberation times; 3. The poor quality of clarity was assessed for churches with longest EDT for the performance of music involving polyphony.

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