Excerpt

'Silence isn't silent,' Noor said. 'What we think of as silence, anyway. Silence is loud. Take this room. Listen.'

Justin listened. It had been a long journey and he was ready to listen. The lab was an expensive facility to hire, and he wanted to be convinced.

They were in a small break-out space at one corner of the small complex. Three low tables, three plastic chairs per table, thick carpet on the floor. In a recess, a machine that made coffee from pods stood beside a sink. Behind lush expanses of triple glazing, the Kielder forest was being stirred by an autumn gale. Stripped of sound, the thrashing branches had a slow, submarine quality, like swaying kelp. As far as he knew, he and Noor were the only people in the building. The only people for miles.

Everything smelled new – the chemical bouquet of fresh carpet, and behind it the sharper scents of paint and cut wood. It was a quiet room, almost silent. But not quite. As Justin stilled himself, he found he could hear the fans of the ventilation system and the muted murmur of machinery.

'There's a refrigerator in here,' he said.

Noor nodded. 'Yes, behind one of the wall panels. You might be able to hear the water in the pipes, too. The air conditioning. Electronics make a sound as well, transformers and capacitors in particular, they kick up a real racket. But that's nothing compared to us, Mr Immerman – we are very noisy creatures. Always wheezing and gurgling and creaking and rustling away.'

Even in black jeans and a plaid shirt, Noor looked neat and professional, and Justin found it hard to imagine she had ever made a noise she did not intend to make. 'Not silent, then,' he said.

'Far from it,' she said. 'The human ear is not a precise instrument. What it perceives as silence is anything below twenty decibels.'

'That sounds high.'

'The language doesn't help. We hear the word decibels, we think noise. Drills, aeroplanes, annoying neighbours. But the scale goes both ways, and it measures quiet as well. Anyway, twenty decibels certainly isn't silence. Silence – true silence, real silence, scientific silence – is much more elusive.'

'So how do we get to zero decibels?'

'Zero!' Noor said, with a smile. 'I think we can do better than that. We can give you subzero decibels, Mr Immerman. The facility is rated to minus twelve decibels, at the edge of what is feasible. The world record is minus twenty. Think of it as a factory, the quietest factory anywhere. And we manufacture one thing: a cube of precision silence.'

Justin had the brochure with him, and he glanced down at the page it was open to – the cube, the room, halfway between the inside of a machine and a torture cell. 'And you do it in this chamber.'

'An anechoic chamber, yes,' Noor said. 'The chamber is soundproofed in all sorts of ways – heavily insulated, of course, built on dampening springs, all the electronics and systems are purpose-built and shielded, and of course we're out here, one of the quietest places in the country, far from noisy town and cities. But it's the chamber's anechoic properties that make it perfect for testing sound. The walls, ceiling and floor are modulated to nullify all sound reflections. You only hear direct sound. No echoes, no reverberations.'

'And that makes a big difference, does it?' Justin asked. He had, of course, read about the anechoic chamber in the brochure, but he had not grasped what made it so different. Sound without echo. What was so special about it? He didn't doubt that a lot of what he heard was echo and reverb, but surely that was only a tiny portion of the whole. Strip it out and what would change, really? He imagined that sound would be more tinny, or more monotonous, as if heard through an old transistor radio.

No, that's not quite it, Noor told him on the phone when he called to ask. It's hard to describe. You really have to experience it. And so he made the long drive to this lonely laboratory.

'It makes all the difference,' Noor said. 'You can be certain that every sound picked up in the chamber is coming directly from the test subject, with no distortion or interference. You will be able to hear the sound it's really making, for the first time. But, if you don't mind me asking you a question, what is it that you'd like to test?'

Justin picked up the steel equipment case at his feet, placed it on the table, and flipped open the clasps. Inside, the prototype lay in a snug bed of shaped foam padding. He was under no illusions about its mundane nature, but he did love opening this case. It felt important and perhaps a little illicit, like the briefcase in Pulp Fiction, or the stolen embryos in Jurassic Park.

'A new generation of air purifiers,' he said. 'As you might have read, air quality is a major consumer concern. Not out here in Kielder, sure, but . . . in the cities.'

Noor smiled. 'Sure.'

'This offers market-leading efficacy in a more compact unit,' Justin went on. 'But, more importantly, it's silent, almost. People have them in their bedrooms, in their children's bedrooms, next to their beds. Where they sleep. They have to be quiet, and most air purifiers are pretty quiet. But these – these are silent.'

'Almost silent,' Noor said, and for a moment Justin thought she might be making fun of him, until he realised she was repeating him. 'And you want to know – how silent?'

'Yes,' Justin said. 'We want something we can put in our marketing, something we can hold over our rivals.'

Noor nodded and, with a look to Justin for approval, picked up the prototype. It was about the size and shaped of a half-used roll of kitchen towel, with a near-featureless body of dark grey plastic. 'Heavy,' she said. 'And it's mains-powered? I see. This should be straightforward.'

Justin found himself looking at the dimpled interior of the equipment case. Its rippling black inner surface made him think of the anechoic chamber. 'May I see the chamber?' he asked. 'Try it out?'

'Of course,' Noor said, but her tone was less than certain. 'You didn't come all this way . . . If you're sure.'

'Why wouldn't I be sure?'

Noor grimaced slightly – a tightening in the muscles of her jaw, as if they had reached an uncomfortable but unavoidable truth. The bill, usually, but it was not that. 'It can be a disturbing place. Even . . . there are some who find it intolerable.'

'A very quiet room sounds pretty restful to me,' Justin said.

The technician shook her head. 'This is far beyond quiet, Mr Immerman. This is . . .' She tapped the side of her head, just above her ear. 'It gets in here.'

Something in her gesture, an undefinable quality connected to a deep and rooted chord, convinced Justin at once. 'Show me,' he said.