The speech intelligibility in a room depends on the reverberation time and the background noise.
If a room has a long reverberation time, spoken words will not die out before the next words reach the listener. This results in poor speech intelligibility, and it will be difficult for the listener to understand what is said.
However, if the sound is absorbed, resulting in a short reverberation time, this provides a good acoustic environment and a high level of speech intelligibility.
Background noise impacts on well-being
A report from the Danish National Research Centre for the Working Environment found that teachers who teach at schools with poor acoustics are less satisfied with their job than teachers at schools with good acoustics. The study found that the most important factor for teachers' dissatisfaction was long reverberation time, which is known to result in a noisy, chaotic acoustic environment.
107 teachers at ten schools in Copenhagen participated in the study, and the desire to change job was six times greater among teachers who taught in rooms with long reverberation times. If the sound level was high for at least one quarter of the working time, teachers were also less motivated and experienced greater fatigue.
Poor acoustics also influenced teachers' perceptions of class unity. The study found that teachers working in classrooms with long reverberation times perceived the social climate in the class as more competitive and aggressive and less relaxed and comfortable.