The classrooms should have short RTs (0,4-0,6 s) and high speech intelligibility rating, but many existing classrooms have RTs of one seconds or more as well as a non uniform acoustic field: this interferes with speech intelligibility, resulting in reduced understanding. The paper reports the influence of the shape and the absorption surfaces distribution on the acoustical performances of the classrooms. The main acoustical parameters was measured in several classrooms with various length ratios and spaciousness. The analysis considers the classrooms obtained from rooms intended for other use: classroom obtained putting together two or three offices and classroom obtained from the restoration of a warehouse. In order to take the acoustical field, in each classroom, in several position of the microphone, was measured the impulse response using a computer based MLS measurement system. The calculation of the EOT and Reverberation Time (T15 e T30) through Schroeder's backward integration of the impulse responses and the calculation of same physical describes as Clarity (C50 and C80), Definition, EOT, RT, STI and RASTI were carried out. The analysis pointed out the limits in the restoration of rooms intended for classrooms in order to advise rules in the classroom's design and in the restorations.

The influence of the shape on the acoustical performance of classrooms

CARDINALE, Nicola;
2003-01-01

Abstract

The classrooms should have short RTs (0,4-0,6 s) and high speech intelligibility rating, but many existing classrooms have RTs of one seconds or more as well as a non uniform acoustic field: this interferes with speech intelligibility, resulting in reduced understanding. The paper reports the influence of the shape and the absorption surfaces distribution on the acoustical performances of the classrooms. The main acoustical parameters was measured in several classrooms with various length ratios and spaciousness. The analysis considers the classrooms obtained from rooms intended for other use: classroom obtained putting together two or three offices and classroom obtained from the restoration of a warehouse. In order to take the acoustical field, in each classroom, in several position of the microphone, was measured the impulse response using a computer based MLS measurement system. The calculation of the EOT and Reverberation Time (T15 e T30) through Schroeder's backward integration of the impulse responses and the calculation of same physical describes as Clarity (C50 and C80), Definition, EOT, RT, STI and RASTI were carried out. The analysis pointed out the limits in the restoration of rooms intended for classrooms in order to advise rules in the classroom's design and in the restorations.
2003
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11563/28853
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