The South China Univeristy of Technology and Dr. Lau of Armstrong have compared the objective acoustic parameters and students’ subjective responses before and after an acoustic treatment in an elementary-school classroom. Acoustic treatment was done by installing sound absorption materials on the ceiling of the classroom for control of sound reverberation. The effects of reverberation time on children’s speech recognition have also been investigated. Results show that (1) the objective acoustic parameters in the classroom were obviously improved; (2) the subjective loudness of different types of noise sources, that students experienced in the classroom, were reduced; and (3) the speech intelligibility was significantly improved in the classroom after the acoustic treatment.
The article can be found from this link.