Why we love sounds of the city jungle

For some, living in a city is a loud, unpleasant babble of intrusive noise. For others it is a soundscape of calming, tones that lift the spirits and brighten the day. Now a £1m, three-year research project is building a database of noises that people say improve their environment. It will translate those findings into design principles to help architects create sweeter-sounding cities.

Among the urban sounds researchers have found to be surprisingly agreeable are car tyres on wet, bumpy asphalt, the distant roar of a motorway flyover, the rumble of an overground train and the thud of heavy bass heard on the street outside a nightclub.

Other sounds that are apparently kind to the ear include a baby laughing, skateboarders practising in underground car parks and orchestras tuning up.

'Sound in the environment, especially that made by other people, has overwhelmingly been considered purely as a matter of volume and generally in negative terms, as both intrusive and undesirable,' said Dr Bill Davies of Salford University, who is leading the Engineering and Physical Sciences Research Council-funded project Positive Soundscapes.

'The strong focus of traditional engineering acoustics is on reducing noise level,' added Davies. 'But not only is that failing, it is also ignoring the many possibilities for creating positive soundscapes in the environments in which we live.'

According to the latest National Noise Incidence Study, moves to bring in quieter transport and urban noise barriers are falling short. Traffic noise is audible in 87 per cent of homes in England and Wales, and 54 per cent of the population is exposed to levels beyond the World Health Organisation guidelines for avoiding serious irritation.

Davies would like to see more water features and sound-generating sculptures next to busy roads. Buildings and trees can also be used to scatter, deaden or reflect sound, to create peaceful, quieter spaces or vibrant, exciting-sounding areas. Experts from five British universities have been bought together by Positive Soundscapes.

Ken Hume of the Noise Research Group at Manchester Metropolitan University, says the project is long overdue. 'Visual aesthetics are a major part of the planning system with strong guidelines determining what is acceptable or unacceptable. A corresponding aesthetics of sound is missing.' Davies is looking for members of the public to take part in mass 'sound walks' through cities or in laboratory listening tests, where the team will use MRI scanners to measure participants' brain activity as they are played a variety of urban noises.

'It is anticipated that pleasurable soundscapes will cause activation in brain areas associated with reward and the opposite will be true of aversive or stressful soundscapes,' said Davies. Early results have shown interesting anomalies in the public's perceptions of sound. 'People can completely change their perception of a sound once they have identified it,' he said. 'In the laboratory, many listeners prefer distant motorway noise to rushing water, until they are told what the sounds are.'

Sounds are not, the study found, judged solely on volume. 'The frequency [pitch] of a noise is a huge issue,' said Davies. 'A high-pitched sound is unpleasant even if it is very quiet, like the whine of a wasp trapped in a room, while a sound like bass coming through the wall of a nightclub, which is loud but low, can be very soothing.'