Improving speech intelligibility in classrooms by decreasing sound energy of low frequency

Abstract

Speech intelligibility is one of the sound field quality evaluation criteria, class-room space needed to create a low-noise and clear listening environment. In addition to the reverberation time (sec), chamber volume (m3) and speech clarity (dB) can tolerate higher use of space and other influencing factors of critical sound energy at low frequency, the spatial frequency factor for indoor conversation came the noise amplification effect will affect listening clarity. Evaluative standard of Rapid Speech Intelligibility (RASTI) for an indoor sound field has been studied for a long time, only 500 Hz and 2 K-Hz cannot be precisely estimated the impact of low frequency noise. After making a Chinese phase and sentence questionnaire for the test, studies will be conducted objective and subjective verification verified statement containing the real class-room space by physical quantities (Reverberation time (RT30, sec) and Signal to noise ratio (S/N ratio, dB) of low-frequency sound energy is correlated between with objective measurement, and subjective test of virtual classrooms is also be made in anechoic chamber to correspond with the low frequency impact factor of speech intelligibility index.