THOUSANDS of pupils may be sitting in acoustic "dead spots" in their classrooms, hearing little of what their teacher is saying, and wondering why.
A study by Heriot-Watt University reveals that most of Britain's classrooms have poor acoustics and pupils' attainment and their teachers' health could be suffering as a result.
The three-year study of conditions in more than 400 schools found that pupils working in rooms with poor sound understood significantly less of what their teacher was saying than pupils in better environments.
A test asking pupils to identify words spoken by their teachers revealed that only 57.3 per cent of words spoken in a crowded and acoustically-unsound classroom were correctly understood. The proportion rose to 67 per cent in classrooms which had been modified to improve acoustics.
Acoustic "dead spots", created by sound waves bouncing off ceiling beams and other obstructions, meant that pupils were suffering disproportionately with some not hearing anything their teacher said.
"These studies were done with the teachers staying in one position, but they indicate that some pupils sitting consistently in particular areas of the classroom could be understanding little of what the teacher is trying to tell them," said Sharon Airey, one of Heriot-Watt's researchers.
"There could be children sitting next to each other, but in different areas of the sound field of a classroom, having totally different experiences," she said.
"We discovered that the majority of primary schools have been designed without classroom acoustics in mind, leading to speech intelligibility problems for the pupils and added stress for the teachers."
Only 10 per cent of classrooms which had not been modified to improve acoustics with lower ceilings, met government guidelines on background noise when they were full of pupils.
A survey of teachers in 129 schools showed that 79 per cent of teachers thought their job contributed to voice and throat problems.
Teachers in uncarpeted classrooms with high ceilings took more days off sick than colleagues in better environments and were more likely to believe that acoustics affected their performance.