Optimal classroom acoustic design with sound absorption and diffusion for the enhancement of speech intelligibility

Classroom design should be focused on the enhancement of the acoustic comfort for students and teachers. Long reverberation times and excessive noise levels can raise vocal effort and negatively affect speech intelligibility. Recent studies and standards updates have investigated whether acoustic treatment should include both absorbent and diffusive surfaces to account for the teaching and learning premises at the same time; however, studies under realistic conditions for the improvement of existing classrooms acoustics are still needed.