Speaking comfort and voice use of teachers in classrooms

Teachers suffer from voice problems more often than the rest of the population, as a consequence of the intensive use of their voices during teaching. Noise and classroom acoustics have been defined as hazards eventually leading to voice problems. In order to make a good classroom acoustic design to preserve the teachers’ voices and maximize their comfort, it is necessary to understand the underlaying relationship between classroom acoustics and teachers’ voice production. This paper presents a brief summary of investigations looking into this relationship. A pilot study, carried out in different rooms, measured significant changes in the voice power levels as a function of the objective quantities volume and support or room gain, which measure the degree of amplification of the own voice in a room. A virtual acoustics system was designed in order to recreate different acoustic conditions in laboratory. Different experiments using this system showed that the talkers’ voice levels decreased linearly with the support of the simulated room. Another experiment aimed to report the relative importance of visual and auditory cues by measuring the voice levels used by talkers to address a listener located at various distances, in rooms with very different acoustics. A field study in schools of southern Sweden found out that teachers with and without voice problems, during actual teaching, are affected differently by the support of the classroom. A last laboratory experiment was carried out to introduce the use of vocal doses for the investigation of voice production under different classroom acoustics and noise conditions, finding that the relative effect of noise on voice production is more important than the effect of room acoustics.