An Investigation into the Effects of Classroom Acoustics on Teachers’ Voices

The acoustic design of classrooms has traditionally focused on pupils hearing the
teacher. There is a need for guidance on the consideration of voice ergonomics for
teachers in classroom design.
This project undertook measurements of teachers’ voices in classrooms with different
acoustic properties to examine possible relationships between voice parameters and
classroom acoustics. The mean voice level measured was classified as ‘loud’ (based on
guidance values) and the participants spoke for a large proportion of the day (average
21%).
Those teaching in rooms with higher unoccupied noise levels spoke with a higher
sound level. There was a significant, moderate, positive correlation between voice
levels in female participants and the unoccupied noise levels in the same region of the
noise spectrum as the fundamental frequency of the female voice. There were signs of
a similar relationship for male participants. This indicated that the control of low
frequency noise levels and reverberation times (not currently covered by schools
guidance documents in England) may be important in reducing voice levels and the
associated vocal risks.
An online survey was also undertaken which gathered 153 responses and included
questions on voice problems, voice training, classroom acoustics and general health.
The respondents reported a number of interesting findings. 66% reported having
experienced voice problems, with many continuing to work despite these problems. A
relatively small proportion of respondents had received voice training (41%), and many
reported shouting or raising their voice.
There were greater rates of reported voice problems in teachers of young children and
those teaching in open plan classrooms. Subjectively the main acoustic issues for
teachers were inadequate internal sound insulation and excessive reverberation.
External noise intrusion was not reported as significant.