Researchers from the department of building engineering and surveying at Heriot-Watt University found "dead spots" in many of the 70 classrooms investigated over three years and sound variations even within the same classroom. The result is that pupils could sit for months understanding very little if anything of what the teacher is saying.
Investing as little as pound;1,000 in acoustics, usually on a suspended ceiling, could distribute sounds more evenly and improve the whole learning environment, as Balgreen primary in Edinburgh has found.
Kathleen Douglas, the headteacher, said: "Staff working in the treated classrooms say there is an enormous difference. Not only do they not have to shout to be heard, but there is a generally calmer, quieter and more relaxed atmosphere in the classroom. We're all delighted."
Sharon Airey, a member of the research team, commented: "We discovered that the majority of primary schools have been designed without classroom acoustics in mind, leading to speech intelligibility problems for pupils and added stress for teachers."
The test classrooms were fitted with acoustic ceilings by Ecophon, a Swedish based manufacturer of ceiling systems which helped fund the pound;120,000 research project along with the Engineering and Physical Sciences Research Council.
Before-and-after comparisons showed dramatic improvements to speech intelligibility and reduced sound reverberations. Another result of poor acoustics, particularly in noisy classrooms, is that staff are more likely to suffer voice and throat problems.