September 9, 2013 – Public announcements in noisy places (e.g. railway stations, airports, sports venues) could become quieter and clearer in future, thanks to new research by experts at the University of Edinburgh.

Scientists say they have developed software that can alter speech before it is broadcast over speakers, making it more audible amid background noise. To improve current synthetic voice technology, researchers studied how speech was perceived by listeners. They carried out tests to pinpoint the components of speech that are most easily heard by people in a noisy place.

Researchers found that, in loud situations, listeners pay most attention to the parts of speech that are easiest to hear, and use those to decipher what is being said. So they developed a mathematical computer program to analyze spoken words and enhance the sounds that help listeners hear what is being said to make speech better understood overall.

In tests, the manipulated speech was found to be much easier to understand than natural speech. In some cases, the improvement was the equivalent of lowering noise by five decibels.

“Noisy environments make it difficult to understand what is being said, and simply making speech louder isn’t the smartest solution,” said Dr. Cassia Valentini Botinhao of the University of Edinburgh’s School of Informatics. “Our findings could offer an alternative, by making speech more intelligible without turning up the volume.”