Scot finds that silence may prove golden

Olga Wojtas discovers the beginnings of a sound revolution that could bring relief to the seven million people in the UK cursed by noisy neighbours.

The old Highland Tollbooth church by Edinburgh Castle is undergoing a Pounds 7 million refurbishment to convert it into the Edinburgh Festival Centre, a year-round focus for arts and culture. It stands at a junction in the Royal Mile, a spectacular setting, but one which means it suffers from a double dose of traffic noise. Acoustic expertise for the project comes from Robin Mackenzie, head of building and surveying at Napier University, who has called for "massive triple glazing". This is designed not only to protect those inside from external noise pollution, but also to protect nearby flat dwellers from disturbance, notably from the Edinburgh Festival Chorus which will rehearse in the centre.

"Environmental Health look after residents very well in Edinburgh, and they don't discriminate between popular music, classical music or noise from washing machines," says Professor Mackenzie. "We went to measure the Edinburgh Festival Chorus, and it's very beautiful but very loud, much louder than road traffic noise. It would be comparable to the noise level on a construction site."

Professor Mackenzie has carried out extensive consultancy work into auditorium design over the past 25 years, including a Science Research Council project for the Arts Council of Great Britain into partially enclosed orchestra pits. This revealed that musicians playing in these conditions for more than ten hours a week were likely to be exposed to illegal noise levels which could lead to deafness.

But his current principal research work, which has attracted grants of around Pounds 800,000, is into developing new materials for sound insulation. This is a key part of the Tollbooth project, which will include offices, dressing rooms, education rooms, a shop and cafe. And Professor Mackenzie believes we are now on the verge of a sound insulation revolution in our homes. "Seven million people in this country are bothered by noise from their neighbours, two million to the extent that they say it's the worst thing in their life," he says.

"A government survey showed that five times as many people complained about sound insulation as about condensation and dampness. People tend to associate noise with neighbours and lack of consideration, not the building itself. But if houses were built to proper building standards, you shouldn't hear your neighbours."

Acoustics is a notoriously under-researched area, Professor Mackenzie says, but manufacturers are now realising that people want to relax at home, undisturbed by neighbours or the rest of the household, and will be prepared to pay for better sound insulation. He was been working with A.Proctor Group, the Scottish-based construction technology specialists, through a teaching company scheme to develop the use of soft-cell polymers to replace traditional material, such as mineral wool. This turns into dust after being walked on repeatedly, and can be virtually useless after five years.

Professor Mackenzie's cutting-edge research, using electron microscopy to look at the structure of materials in a bid to develop fundamentally new designs, has been boosted by industry's new interest in designing from first principles.

"We've never had that luxury in the past. I've always had to go to shops to buy what's there, but in the past couple of years, the multinationals have begun to see this as being a big market. I think it's an appreciation that in an advanced western society, we're unwilling to put up with noise."

Sound insulation is much more complex than thermal insulation because it has to cope with a range of frequencies, Professor Mackenzie says. "Timber construction will typically give very, very good insulation against speech, but very poor insulation against a low frequency stereo. A concrete floor is very good at low frequency, but less good at high frequency. You have to look at different housing types and design accordingly."

At present, sound insulation is virtually the only area of building regulation which is not tested, he says. He believes that Scotland has taken a lead in research because its building control officers have traditionally carried out sound tests to check on workmanship.

"If sound tests aren't mandatory, there's much less incentive for contractors to get it right. You don't have sound insulation tests in England, so you get some pretty poor insulation."

But the European Commission has now produced a draft directive which may lead to mandatory tests, less because of noise pollution than because of the desire to standardise building regulations across the European Union. And manufacturers' interest would burgeon as a result.

Meanwhile, Professor Mackenzie's consultancy is also involved in the acoustic design for a new Edinburgh cinema complex. "It has to have absolutely massive sound insulation, because you're talking about massive noise in something like The Lost World. We're building a box within a box, in which each cinema is floating on huge polymer pads to stop the noise of dinosaurs interfering with the love story next door."