Objective and subjective speech intelligibility assessments in primary school classrooms

摘要

This work describes the results of speech intelligibility tests and measurements performed inprimary school classrooms. The analyses were carried out in two laboratory-classroomscharacterized by 1.6 s and 0.7 s occupied midfrequency reverberation time (RT), in presence ofdifferent types of noise. Speech babble and fan-coil noise were emitted into the room, trafficnoise came from an external source and impact noise was generated on the floor upstairs theclassroom. A total of about 3700 tests were submitted to 470 students from 7 to 11 year olds.The correlations between speech intelligibility and objective parameters are obtained forchildren of different age. The availability of data referred to two different conditions, with highand low RT respectively, allows to determine intelligibility decrease due to reverberation. Afurther research outcome is the effect on speech intelligibility of the different types of noise.One of the main finding of the work, as found in a previous research, is that youngerchildren need more restrictive acoustical condition than older ones, for achieving the same levelof speech intelligibility. A good correspondence was found between speech intelligibility andlistening difficulty, the latter evaluated on a 5-point scale from “very easy” to “very difficult”.