Acoustics
AS MY HEARING SLIPPED AWAY, I realised something odd. Until it actually started to happen I’d just assumed that, as I became deafer, things would gradually just get quieter and quieter, as if every year someone was sliding another layer of glazing into the space between me and the world. But this wasn’t like that. Yes, the volume was definitely going down, but the odd thing was that deafness wasn’t making me less aware of sound, it was making me more.
Having been indifferent to acoustics, I was … well, not obsessed with it exactly, but it certainly seemed to occupy a lot more space in my life. Up until then I’d never really thought about the difference between the sound in a room with high ceilings and in a room with low ceilings, or why it was that some streets sounded softer than others. Did it really matter if you all sat in the big main room of a pub or squeezed yourselves into one of the snugs? In hearing terms, was there really much of a discrepancy between a double-glazed 1960s tower block or a suburban house near a busy road? Why should one large impersonal meeting room feel private while another sounded like drumming on dustbin lids? Was there any real difference between a floor of stone or of wood?
Previously I suppose I might have noticed that there was a difference between the way sound behaved in a cold winter hall or in a warm front room. But when I walked into someone’s house to meet them for the first time, acoustics wasn’t generally the first thing on my mind. Pre-deafness, I’d be thinking about the person themselves or what they’d said their son’s name was, or – if I was interviewing them – what questions I needed to ask. Now, first thing, I’d walk into the room and start figuring out the ratio of tiling to lino or try to work out how I was going to get round the noise of their washing machine’s spin cycle. I wasn’t concentrating on them any more, I was concentrating on their environment.
I’d also started noticing that sound had different shapes. The way someone’s voice sounded when they walked beside me down a street versus the way they sounded when they walked across moorland. The difference between a shopping centre’s open spaces and its overstuffed shops. The funnelled passageways of the Northern Line or the vaults of Baker Street. DLR versus Overground. Victoria Line versus Central. Grass versus concrete, metal against glass. Which was easier: a conversation with someone near a school at breaktime, or the same conversation by a building site? Taxis, sheds, warehouses, stations, barns, old houses or new ones. Every single situation had its own particular sound, and that sound would alter depending on the number of people and the atmospheric conditions.
Exchanges with friends or colleagues started to take on a pattern. We’d agree on a date and a time and then everything would grind to a halt for a stand-off over destination.
‘What about Mash?’ they’d say.
I’d remember the scrape of crockery and the roar like an aircraft hangar. ‘Sort of,’ I’d say, ‘or the local Chinese?’, my thinking being that, OK, so the local Chinese might have been twice condemned by the Food Standards Agency, but at least it had carpet.
There would be a pause. ‘The Eagle?’
Me: ‘Or a deserted curry house in Hornsey?’
I’d sit there, fingers hovering over a two-sentence email, wondering just how far I could push this before gaining a reputation for being a complete diva. How could I say I’d rather meet in a place with coleslaw and no atmosphere than somewhere where it might take me twenty minutes to figure out what the waiter had said? Was it better to go to a meeting in a noisy coffee chain and have people think you were a weirdo for staring fixedly at their lips the whole time, or confess and meet on a park bench near Bayswater like characters in a Le Carré novel?
It seemed like such a small thing but our priorities seemed to be pulling apart. My friends wanted to catch up and have something decent to eat. I just wanted to know whether they were speaking English or not.
IF YOU HAD HAPPENED to be in Glasgow in the spring of 2015, and if you had happened to be standing on the north shore of the Clyde near Glasgow Harbour, you would have been able to look over at the opposite bank and see a great steel shape filling the far right entrance of the big shed at the Fairfield shipyard. Except for a slight in-dipping as it nears the ground, the shape is almost square. Its sides are painted red and the face nearest the riverside is sliced by horizontal lines, each one representing another deck level. All over it there are people in overalls moving up and down the scaffold stairways trailing cables or angle grinders. The big shape slots into the shed’s entrance so precisely that it takes a couple of moments before you realise it isn’t just part of the permanent structure, an illusion reinforced by the scaffold stairs jumbling their way up the front and the shrink-wrapped spray booths barnacled to the shape’s side.
The shape is a cross-section of an aircraft carrier, a slice of ship split right down the middle. It’s just one section of HMS Prince of Wales, the second aircraft carrier being built at Govan for the Royal Navy. When it’s finished it will function as a medium-sized floating airbase complete with hangars and workshops and a 280-metre flight deck tailing off over the sea. The first carrier, HMS Queen Elizabeth, is already over at Rosyth on the Firth of Forth being fitted out.
Over on the south side of the river the view is different. Once through the security procedures and the official preliminaries I’m given a set of white overalls, a pair of boots and a hard hat. My escort, Derek McCaffrey, the Operations Manager for the build, takes me out and round past the docks.
There’s been a shipyard on this site since 1834 and during that time a whole township of roads and junctions has built up. Over there towards the roadside are the Edwardian management offices, now boarded up, and below our feet lies the lacework of cobbles and rails from the making of ships in the golden age. Back in the 1960s when Sean Connery was still licensed to kill, he made a documentary called The Bowler and the Bunnet on the bad blood between management and workers in this yard. One of the scenes shows him riding round one of the sheds on a bicycle, a big man made insignificant by the huge steel hollows. Painted walkways on the roads show people where to walk and where not to walk, and when work starts in the morning and ends in the evening, there’s still the same mass movement of population heading towards the gates as there was back in the days when they built the SS Stirling Castle.
Over there on the left hand side of the dock is the newly built bridge of the aircraft carrier, all wonky diagonals and pixellated angles, and round the front of the big shed the carrier suddenly rears up in front of us.
‘Are you OK with heights?’ asks Derek.
Yes, I say.
‘That’s lucky,’ he says, ‘because there’s a lot of them.’
We climb and climb, rising up the rigging, and with each step we ascend, more and more of Glasgow becomes visible. Up on the top deck of Lower Block 3 (or LB3) itself, I can see the whole skyline of the city with the Clyde directly beneath. Think of a twentieth-century British ship, any ship you’ve ever heard of except for the ones that sank, and it was almost certainly built along this stretch of water. Looking at the river now, the idea seems ridiculous. This river is tiny – a water feature surely designed by estate agents to add value to riverside properties. You couldn’t fit a canoe on this thing, never mind the Queen Mary or the QE2 or this section of supercarrier standing on the bankside sliced like a steel cutlet. Still, according to the plan, once each section is completed it’s jacked up onto a transporter, inched out of the shed, loaded onto another ship, pulled down the river and transported round the whole coast of Scotland. Once it’s reached the Firth of Forth it’s then towed up the estuary and under the bridges, and finally joined together into a finished ship at Rosyth. By land, that journey is about forty miles. By sea, it’s 600. The UK doesn’t have a shipyard large enough to build this ship in one piece.
Directly above us is the roof of the shed. Below our feet is the top deck, and nailed to that deck are a series of small temporary huts for welding or storage. Behind a milk-white veil of polythene, a shadow-man stands spray-painting components, and over there beside the spools of coloured cabling the electrics are being sorted into strands. Beyond that in another cabin, three men are picking over drawings. Looking over at the tiny gap between the hull and the walls of the shed it’s just about possible to imagine this as something that might one day move, but down below in the cabins full of sockets and pipework it just feels like the seventh floor of a rather gloomy office block. When it’s finished, this ship will be a seaborne city, with doctors, dentists, admin staff, swimming pools, four separate canteens, plus of course a lot of kit for killing people. No wonder BAE have produced a mobile app to help people who get lost in the ship’s innards. Are they really worried about people disappearing for good?
‘Oh God, aye!’ says one of the laser cutters cheerfully.
So has anyone needed the app yet?
‘Maybe,’ says McCaffrey. ‘But they haven’t admitted it.’
As the four of us return slowly to earth down the scaffolding, he looks back up at the bulk behind him. ‘That’s my baby,’ he says.
Will he miss it once it’s gone?
‘I always miss ships when they go, yes.’ The finished aircraft carriers are too big for a ‘dynamic launch’, the old-fashioned champagne baptism down the slip, ‘but she does get named’.
So, despite Lloyd’s 2003 announcement that from now on ships should no longer be considered feminine, does he still think of the carrier as she?
‘A ship is always a she. What do Lloyd’s know? We build her. She belongs to us.’
We look up at it again, craning our necks so far back that the tips of our hard hats brush the collars of our overalls. This ship has already taken months and months, thousands of hours, millions – billions – of pounds, all the uncountable thoughts, dreams, ideas, arguments, ambitions, revisions and speculations poured into it. It doesn’t matter what it’s called or how it’s made, it’s still the sum total of all the human energy that already belongs to it.
Back in the spring sunshine, we walk over to another building. I’m still overawed by the size of LB3, but the fabrication shed impresses in a completely different way. In through a little door in the wall and suddenly you’re in a cathedral, a great secular cathedral designed for the worship of steel. The roof is way up in the dimness above and the light from the riverside streams in sideways, illuminating asymmetric slabs of metal laid out between taped lines along the floor. All the ground space has been divided into little rectangular fiefdoms – shot-blasting there, laser cutting here, a panel line for bulkhead assembly three miles to the left. Huge yellow gantries lift and reposition steel plates and over in one corner there’s a giant flat bath filled with water over which a laser hovers, ready to razor out bits of ship accurate to within millimetres. To the south a group of men are welding T-bars and brackets onto some of the steel sections while over in the far west territories Jeremy Vine is talking to himself on Radio 2. Somewhere over there, about half a mile away there’s a mocked-up section of a Type 26 destroyer, lots of square sections of space within a vastly greater one.
And it’s noisy. In acoustic terms this place is a perfect echo chamber, a space designed to sweep sound straight back to you. The roof feels about six miles high and the floor space is – entirely literally – big enough to house a battleship. Or two. It’s April, but it’s still bloody cold in here. Even the welders are wearing balaclavas or beanies under their hard hats and the chill only amplifies things further. All the things which might absorb noise (wood, fabric, plastics) are absent, which means that there’s nothing to fill the air except pigeons and that every wave returns for a second sounding. The walls of the shed are steel, the plates of the carrier are steel, the machines with which the plates are cut are steel. The floor is concrete and there’s a river outside. Everything, every surface, every object, every material, is reverberant. Somewhere a long way away someone drops a wrench and as it clangs you can hear the sound flash out, hit the sides and ride down the building. It makes voices seem mousy and foolish and it means that people don’t talk much until they’re in a place in which they feel themselves back at the right scale again.
It might seem loud now, but in reality this place is a mere whisper of what it used to be. Partly that’s because this yard is working at a fraction of its potential capacity. Partly it’s because the way ships are constructed has changed. And partly it’s because of health & safety. Within each metal fiefdom there are now bright HSE notices directing staff towards good behaviour, colour-coded notices insisting on your attention to RIDDOR or COSH or heavy-lifting legislation. Everyone’s wearing the proper gear – overalls, hi-vis tabards, hard hats, goggles, welding gloves, workboots, breathing apparatus or dust masks. And almost everyone in here, whether they’re welding or drilling or chalking up plates, is wearing ear defenders.
It wasn’t like this in the past. When shipbuilding first took off here in the late nineteenth century, the yards were so constantly, overwhelmingly noisy that workers developed a basic form of sign language between themselves in order to communicate at all. Within some trades, deafness was so ubiquitous that it was taken as proof of experience. Just as no one quite trusted a riveter with a full hand of fingers, so no one would dream of hiring a forge operator who could actually hear. In 1886, a Glasgow surgeon named Thomas Barr examined a group of 100 shipyard boilermakers and found that ‘not one of them had normal hearing’. Three-quarters of the group were deafened to the extent that they were either partially or entirely unable to hear someone speaking at a public meeting. Barr found equal levels of deafness among locksmiths, iron-turners, railway workers and weavers. Their employers, the shipyard owners and industrialists, weren’t much bothered. Since deafness didn’t stop workers doing their jobs, deafness wasn’t a problem. The prevailing attitude then was that a worker could have three tongues, seventeen toes and not a single sense remaining, just so long as none of those things damaged their economic viability.
Even with Barr’s work and the beginnings of legislation offering some protection to workers’ rights, hearing loss remained more of an anecdotal problem than a legal issue. Until well into the 1970s it was widely known that some professions suffered more from hearing loss than others and that some occupations – particularly those within heavy industry – carried a much greater risk. The supporting science began to build up and further studies began to isolate the exact point at which repeated exposure to loud noise would begin to damage human hearing.
But still, it took a long, long time for anything to happen. When V. S. Pritchett visited several British shipyards working at their wartime peak, things were, if anything, even worse than when Barr had made his investigations. In a pamphlet written for the Ministry of Information and published after the war’s end in 1946, Pritchett made it clear how overwhelming the shipyards could be:
The noise of the [ship]building reaches a note and volume which are unimaginable. From a distance it sounds like a thick gale of wind in a forest; in the yard itself, as the rivetter’s sparks dribble down from the ship’s side, you seem to have got into the hot corner of a gunman’s skirmish. In the yard you could hear if you shouted. Here, your shouts are knocked clean out. You have to dodge around a corner and hope one word in six reaches the ear that is leaned towards you. The roar comes from above, below and on either side of you, a pandemonium of clangings, rappings and sawn-off gun-work with men making rival roars in an alleyway a yard wide that at first causes terror as you grope through the darkness. Hundreds of men seem to be lying, kneeling, crouching, crawling about … Once in a while, a face which has gone beyond indignation and resignation into a world of its own looks up from the level of your knees … You look down in to the body of the ship through the smoke haze of the rivetters’ fires and watch men step about there like little demons in the galleries of Dante’s Hell.
Then as now, a warship was a complex organism and there might be 13,000 steel plates in its making. Beside the forge, ‘Each man,’ wrote Pritchett, ‘stands by his hooded fire, his face smoky and reddened by flame and glistening with sweat.’ He sees the concentration of the men near the forge, and watches their snake-killing dance as they lift the red-hot framing strips out of the fire and drive them with dogs and clamps to shift them from straights into S-bends. He watches the woman working the crane communicating with hand signals: one finger for stop, and two for go. And he notes the particular quality of sound in a ship: ‘The rivetters’ and caulkers’ fusillade, the platers’ solemn clang, and the elephantine thumping of the forge. These steel hammers that come down like tree trunks on the anvil shake the earth and the building and thicken the air with a cloud of reverberations.’
Welding was introduced in most British yards during the 1940s, but for the moment each plate would be joined to another with rivets – a million or more in the making of a ship, and all of them forged on site,
The riveter is a member of the ‘black squad’, a gang of four who turn up to the job with the misleading nonchalance of a family of jugglers. [The black squads] can set up shop anywhere and begin performing their hot-chestnut act. You see one swung over the ships’ side. He stands on his plank waiting with the pneumatic instrument in his gloved hands. On the other side of the plate, inside the ship, is the heater with his smoking brazier … he plucks a rivet out of the fire with his tongs, a ‘boy’ (nowadays it is often a girl in dungarees) catches the rivet in another pair of tongs and steps quickly with it to the holder up who puts it through the proper holes at the junction of the plates. As the pink nub of the rivet comes through, the pneumatic striker comes down on it, roaring out blows at the rate of about 700 hits a minute, and squeezes it flat.
An expert black squad, he notes, could manage about thirty-seven rivets an hour and there would be several squads working their way down the length of the hull. Since those men were all paid piecework, there was every incentive for all of them to bang away as hard and as fast as possible.
The noise – and the pain of that noise – was indescribable. Even now, with forty-odd years of HSE legislation, so much steel in such a great space is still loud. But back in the forties and fifties, for ten or more hours a day six days a week, the boilermakers, the riveters and the black squads existed in a world without quiet, perpetually exposed to between 120 and 150 decibels. They lived within a state of extremity – extreme scale, extreme heat, extreme cold, extreme noise, every sense perpetually overwhelmed:
The individual is least, the group alone seems to have personality [wrote Pritchett]. And then, the sounds: this great and diabolical religion … great and sudden clangs, an intoned mutter … bell-like, gong-like crashes which astound the ear and the mind. You feel you may be watching a rite devoted to the creation of the ship which belongs naturally – before anyone else – to those votaries who are building her.
Back in London and writing up his experiences, he noted, ‘It is the silence of the people in the noise of these yards which you think of afterwards.’
But, as the machines slowed to a stop on heavy industry during the second half of the twentieth century, the yards reverted to other sounds; the surrounding city, the river. In 1984, almost a century after Barr’s identification of the damage caused to boilermakers’ hearing, a landmark case finally established that employers could be held liable for that damage. Once the Noise at Work Act was passed, the responsibility for protecting workers’ hearing passed to management. As understanding of the issue increased, so health and safety spread, and over the past 40 years, acoustics has become a standardised aspect of new construction contracts. In theory, we’ve now reached a point where no one should lose their hearing just for doing their job.
VICTOR HUMPHREY is a professor of engineering acoustics at the University of Southampton’s Institute of Sound and Vibration with a particular speciality in research into marine and ultrasonic sound. He works in an old sixties block which he has filled with what appear to be the fruits of several decades’ worth of study and lecturing – papers, books, photographs, drawings, models, instruments, things put there specifically and only in order to gather dust. He himself is tall and healthy looking, with thinning grey hair scraped forward and a habit of smiling faintly to himself when he says something technical. The smile is not meant to convey humour, but is a cross between a nervous gesture and a device for bridging the gap between the information and the listener. He starts off cautiously, punctuating his observations with thoughtful exhalations because – as he says – he’s trying ‘to get things absolutely right’. After about a quarter of an hour he becomes warmer and more enthusiastic and by the time I ask about the anechoic chamber, he’s lit up like a small boy.
Human hearing, he points out, has been given a bad press. Compared to the fantastic whizz-bang capabilities of birds or whales, our ears have always been portrayed as a bit dim – no more than a detuned huddle of mid-range frequencies deaf to the great ultrasonic symphonies playing all around us. But, as Humphrey points out, human hearing is no less miraculous than that of a dog or a bat. Our bandwidth (our frequency range) may be narrow, but our capacity for amplitude is not.
Think of sound as a wave again. Think of that wave becoming the power (energy) required to make the eardrum vibrate. ‘We get our students to measure the amount of power that’s radiated by a loudspeaker. So we put a loudspeaker onto the table, switch some noise onto it and ask them how much power is being radiated. They’ll say things like one watt or ten watts. And we then measure that power. So if it were a light bulb and you put a hundred watts of power into it, you don’t get a hundred watts of light out of it. Same for the loudspeaker – how much acoustic power is coming out? The acoustic power is .00001 of a watt. So the sound power is very small – very little energy. That’s what’s so amazing about hearing. It’s just incredible, the hearing system, when you work out how small a pressure and what range of pressures you can detect.’
So the fact that we can hear birdsong through a window is really extraordinary? ‘Yes. It’s amazing the range of things we can hear, from the quietest thing to the very loudest, the sound that gives pain. That range is about a million in pressure variation. The quietest thing we can hear is a million times smaller than the things which would cause us pain.’
To illustrate his point he takes me out of the building through what seems like several other buildings, up stairs and down corridors to a big ground-floor passageway. Halfway along it is a big, high-ceilinged chamber covered in long wedge-shaped foam tentacles which reach all the way up the walls and hang down from the ceiling. In some parts of the room they stick out with such geometric regularity they create a sense of 3D illusion, but in others they’ve begun to droop, which makes the whole place seem flabby and worn. Below our feet is a metal grille laid in squares, and below that are more tentacles. Humphrey does not close the door, but even standing in the unsealed room is enough to give a sense of a place in which almost all sound has been muffled, as if each word had been coated in velvet. When he claps his hands, the sound is small and disappears immediately. Despite the cold, I like the room – it makes speech and understanding seem effortless, though when I play it back the space translates as something tiny, as if Humphrey and I were talking to each other in a shoebox.
As he explains, the point of the room is that it has no resonance and so no echo. The foam on the walls stops the bounce of a wave, thus the only sound coming to us is coming direct from the source. In here, there are no sound waves pinging off flat surfaces so if someone standing to my right says something then I’m only going to hear them in the right ear, not the left. Mono, not stereo. It’s exactly the effect that sound engineers try and create in a radio booth: fabric and absorbent baffles on the walls, small space, nothing to dissipate the single-source strength of a voice.
Humphrey takes me out of the chamber and into the room next door. This is the anechoic opposite, a resonance chamber. The room is large, rectangular, with a very high ceiling and wooden baffles hanging down at intervals. There is no absorption in here, nothing to receive the echoes, so all the noises we make – our footsteps, our voices – return indefinitely. There is so much reverberance in there it’s like listening to the distant sling of tube trains approaching down the rails. Or a Glasgow shipyard. When Humphrey walks a little farther away, the reverberance becomes so great that it becomes difficult to pick up what he’s saying. I have to watch his face much more carefully to hear him than in the anechoic chamber, and when he claps it sounds like something huge and flat dropped on the floor. The sound remains for minutes afterwards, making the space feel far bigger than it is, as if the size of the room is an illusion and we’re both now lost in a mess of echoes. You would be able to hear a tiny sound in here, he points out, because even if your ears hadn’t picked up the original source the reverberance fetches it back to you.
As Humphrey explains, the resonance chamber is designed partly to allow students to measure the power of sound from a particular source. So, for instance, they could put someone in here with a snare drum and then measure the pressure waves given off at different volumes. But because the sound in here is so bouncy, it’s very difficult for the ears and thus the brain to sort out the source from the echo.
‘I have to be standing closer to you in order for your hearing to recognise me as the dominant sound source rather than just one of the different reverberances,’ he says. ‘I’m trying deliberately to talk slower in here, but if you can imagine having a sound source in here as well, it really is quite difficult. And these baffles are designed to make that sound even more diffuse.’
It’s interesting, I say, that the two rooms have such a strong psychological effect. The temperature in both rooms is exactly the same, but this one seems colder. Standing in here I just want to be next door in the anechoic chamber where the sound is so much softer. This place is like … well, it’s like half of Britain’s bars.
Humphrey agrees. ‘The problem with restaurants is that the designers like smooth, flat, shiny surfaces.’
Is that because they want to create the illusion that there’re lots of people?
‘Yes, but in general the problem is that it makes it difficult to have a real conversation. Absorption in room acoustics is what fraction of sound is reflected back from the walls. With a flat concrete wall like this, most of the sound would be reflected back so the absorption would be very small.’
As Humphrey points out, the irony is that what has now been outlawed as dangerous in the workplace is now actively encouraged outside of it. Great care and forethought has gone into making bars and restaurants as acoustically uncomfortable as possible. If three or four couples are talking to each other in a room full of curtains and soft chairs, they vanish. Put exactly the same eight people in a room with brick walls, high ceilings and a sound system, and suddenly they’ve become sixteen people, or twenty, or forty. From a restaurant’s point of view they’ve just generated treble the covers for none of the price. Suddenly, this place – this empty-ish tapas bar, this Sunday Thai – sounds like something happening. So now there’s a buzz about the place and that buzz is drawing in more people who have come to see what all the buzz is about. And in order to be heard above the rising volume, everyone has to lean in close to each other. The restaurant has created a space in which everyone is having trouble hearing, so everyone’s begun to amplify their gestures and stare at each other’s faces. Now they’re not thinking about work and babysitters any more, they’re thinking about sex. Plus, of course, the shouting has made them thirsty, so they’re ordering more drinks. It’s clever, really, until you realise that the reason for eating out is not the ambience or the buzz or even the food, it’s the people you sit down with.
I look up and point to the ceiling of the resonance chamber. Does it make a difference that it’s high? Humphrey nods. ‘It has an impact on reverberation time, the volume of the room. And the walls in here are not parallel and the ceiling is not flat.’ Why does that make a difference? ‘If you have parallel walls, you tend to get some modes where the sound is just bouncing backwards and forwards and it builds up a standing wave in that direction. With walls like this, you don’t get that and the sound is more uniform from place to place.’
He leads us out of the resonance chamber and into another area, in which a tiny booth has been constructed out of plywood boarding. The room has four amps – two at knee level and two at head height – and a series of small microphones poking out of the ceiling at regular intervals. Outside the booth two Korean students are tinkering with several mike stands to which are attached a cluster of loudspeakers. When Humphrey asks them what they’re doing, they say that they’re trying to construct a 22-channel sound system, a ‘virtual soundfield’.
What do you want to do with it? I ask. Home entertainment, they say. So the aim is to sit in your flat and watch Spartacus: War of the Damned as if half the Damned were in the room with you? The two students nod enthusiastically. ‘That is correct,’ one of them says, ‘It will be a more realistic feeling.’
In fact, points out Humphrey, they could go one better and have completely different sound sources for each speaker, so if they stood in one corner of the room they’d hear a male voice and if they stood in another they’d hear a female voice, thus allowing them to get to know the Damned on an individual first-name basis. Both students look at him like they’ve just had some kind of profound spiritual experience. ‘Yes,’ says one of them eventually. ‘Yes.’
He leaves them to it and leads on. At first, the final room he shows me seems to have little to do with acoustics. This is the Human Factors research lab, a double-height space with a walkway at first-floor level and a deep pit at its centre. In the pit is a hydraulic lift topped with a stage, and on the stage is the chassis of a car. The lift can move on six different axes and its job is to shake like a road. Should you require it to, it can be programmed to simulate, say, a ten-minute ride through the New Forest or a five-minute drive across potholed city backstreets. Just above us is a TV screen on which is playing a vehicle motion test on seat suspension – a man strapped into half a car – and behind him is a computer simulation of a pre-loaded road journey. The car is stationery, but it is twitching in sync with the imaginary road.
On the right-hand side of the room there’s a separate free-standing walkway which is designed to measure people’s ability to function on board a vessel tilted at various angles, and elsewhere in the room they’re testing machine tools like pneumatic drills or domestic sanders. Acoustics and vibration – and the way they’re experienced by the human body – are so closely related that there’s no point in trying to separate them, so this place does everything from testing Formula 1 cars till the nuts rattle to streamlining members of the British Olympic cycling team for wind resistance.
Acoustic science is both very old and very young. The effects of air or water on sound have been anecdotally understood for a long time, but Southampton is filling out that understanding and then applying it directly. To make ships and submarines quieter, the military have invested heavily in research into underwater acoustics. In addition to all the other established medical applications such as dissolving kidney stones, ultrasonics are now used to treat some cancers or establish the state of a patient’s bone health. Business has got in on the act – dentists and shopping centres now routinely spend money on creating soundscapes designed to lull punters into a more pliant state. Acoustics, in other words, has gone from a state of almost non-existence 50 years ago to a science whose reach ripples wider by the day.
All this new research going on at Southampton and elsewhere only deepens our understanding that sound is a phenomenon with a potentially infinite number of attributes. If, instead of thinking of it as just noise, we thought of it as pressure or saw it as curves in the shape of time and space, then perhaps it would be easier to grasp its potential.
‘Geology,’ says Red in the film The Shawshank Redemption, ‘is the study of pressure and time. That’s all it takes, really. Pressure, and time.’ As for geology, so for sound. And as for sound, so for the people who experience it.