Sydney: Researchers have found that connecting teachers to a sound system can dramatically improve pupils' test results and reduce classroom disruption.

Using a microphone and a radio transmitter, what the teacher says is broadcast using speakers around the room. Pupils are able to hear more clearly, and teachers do not strain their voices.

Stuart McLaren from the Institute of Food, Nutrition and Human Health and Steve Humphries from the School of Psychology surveyed teachers and tested pupils and classroom acoustics at primary schools in Auckland and Wellington.

Tests given to pupils when the system was in use showed an increase of up to 60 percent more correct answers.

Teachers also reported significant improvements in attention, cooperation and understanding of verbal instructions among pupils, major improvements in behaviour and quieter classrooms.

They also noticed they were less likely to strain their voices to be heard and, as a result, were less likely to become tired.

The research was funded by a private education trust, which is considering investing in sound field systems.

In one classroom, pupils' ability to hear and interpret instructions from the teacher was tested with and without the system.

McLaren said the research differs from previous studies in that it tested systems when noise was introduced to the classroom to imitate heavy traffic and heavy rain.

Even in quiet conditions, with pupils listening attentively, a significant improvement was noted with the number of correct scores in the listening test obtained with the system turned on. In a noisy classroom, results were more dramatic.

Bernadette Murfitt, a teacher at St Frqncis Xavier School, the venue of the study, said the system, which has been installed for nearly two years, is easy to use and means every child is able to hear his or her teacher speak. "It's made a big difference for our children." IANS