Experimental comparison between sound sources with different directivity in investigating acoustic properties of selected classrooms in elementary schools

摘要

Acoustic properties of classrooms can be assessed with parameters that are used to characterize indoor acoustics, e.g. reverberation time, early decay time (EDT), speech intelligibility index (STI), articulation loss of consonants ((percent)ALC), clarity index (C_(50)), definition index (D_(50)). In the Laboratory of Noise of the Central Institute for Labour Protection - National Research Institute, those parameters are considered when estimating teachers' exposure to noise and developing guidelines for designing classrooms. Some research has shown that directivity of the sound source has a significant influence on the results of impulse response measurements. This paper presents measurements conducted in selected classrooms in elementary schools with several different sound sources.