Effectiveness of speech intelligibility from length and width changes of classrooms with similar volume

The interaction between student and teacher and consequently the educational performance in the classroom is significantly influenced by the student's understanding of the teacher's speech. Given the impact of the speech transmission index(STI) on the physical conditions of space along with human factors, it can be expected that creating favorable environmental conditions in these spaces to create appropriate acoustic conditions will improve quantitative measures related to speech Intelligibility and thus improve the performance of the spaces.In previous studies, researchers often focused on background noise level as an external factor or the use of soundproofing materials in walls or interior surfaces and the effect of changes in the length and width of spaces in the same volume that have equal computational reverberation time have been Less paid. Therefore, the effectiveness of speech intelligibility of listeners with the same conditions and position relative to the sound source in spaces with different lengths and widths but with the same area and volume, is the purpose of this article.Here, an attempt has been made with a descriptive-analytical approach through simulation with ODEON software to produce the necessary data for statistical tests and especially correlation test in order to investigate the effectiveness of STI values in fixed receiver points in spaces of different lengths and widths.According to the findings of the statistical tests, increasing the length as well as increasing the distance between the receiver and the lateral surfaces, in spaces with the same area and volume, reduced the values of the STI.