The air on Mint Street is heavy with the clang and clatter of the 08:15 to Liverpool Street station. The east London estate is squeezed into a small space beside a curved train line, and the carriages squeal as they round the bend. All conversations freeze until the racket is over, then a few words are passed between neighbours before the next train comes.

Stand on the pavement and the sound is thunderous, but step inside one of the flats and you can suddenly hear yourself think. A double-glazed indoor balcony full of potted plants buffers the noise to nothingness.

London is densifying. For people not to wring each other’s necks, you need to keep the neighbourly love going Ivan Harbour

“In my flat, we have vent ducts installed in the ceiling,” says resident Nick Butcher, 35. “They connect to the quiet courtyard side of the building, not the noisy front, so I don’t hear the trains.”

The Mint Street estate – a mix of affordable rent, shared-ownership and private sale apartments – was completed by Pitman Tozer architects in 2014 and is managed by the social housing association Peabody. Its 67 homes occupy a site that was previously industrial and considered too noisy for living, but its indoor balconies and courtyard-facing air ducts are innovative ways to stop the boom of a railway breaking into people’s lives. In fact, the only noise complaints from residents have been about children playing in the gardens at the back.

Noise from the pedestrianised Sai Yeung Choi Street South in Mong Kok, Hong Kong caused local residents so much distress city authorities reopened it to cars. Photograph: Philip Fong/AFP/Getty Images

“London is densifying,” says Ivan Harbour of the architecture firm Rogers Stirk Harbour + Partners. “For people not to wring each other’s necks, you need to keep the neighbourly love going. One way to do that is to make sure that you get peace and quiet.”

The wider issue is one facing cities across the globe: how do you deal with the noise of densification?

The biggest din

The UN predicts that, by 2050, two-thirds of people will live in cities. India is projected to have another 416 million urban dwellers than it does now, with China adding 255 million and Nigeria 189 million.

And as cities swell, there are signs we are finding it harder to cope with the noise. In Britain, for example, the government’s most recent National Noise Attitude Survey found “a strongly statistically significant increase” in the proportion of respondents who reported being disturbed by road traffic, neighbours, aircraft and construction.

It is the poor who face the biggest din. In the US, research from 2017 suggests poorer urban neighbourhoods are nearly two decibels louder than affluent areas. Noise pollution tracks social segregation. The same study also found that, across US cities such as Detroit and Chicago, communities with larger proportions of black, Hispanic and Asian residents face higher noise levels than other neighbourhoods.

Noise isn’t only an irritation. Recent studies suggest it can have dire effects on people’s health. High blood pressure, heart attacks and type 2 diabetes are just some of the illnesses doctors have linked to long-term exposure to city clamour, with the European Environment Agency chalking up 10,000 premature deaths a year in Europe to noise.

Noise barrier by autobahn in Essen, Germany. Photograph: Jochen Tack/Alamy

In 21st-century cities we have to contend with sirens, drills, shouts, rumbles, bangs, screams, barks, crunches, beeps, moans and babbles only a wall away. As our homes, schools and offices cluster tighter together, what can we do to stop the ruckus?

The social housing on Mint Street comes with built-in noise control, but elsewhere silence is a premium commodity. If you live in New York and have $24,000 (£18,300) spare, you might be able to treat your ceiling with mass-loaded vinyl and hang it on springs, or place your radiator pipes on sound-isolating mounts. In Mumbai, acoustic consultants for cinemas are selling soundproof walls for home use, but at prices only the wealthy can afford. Another option may be to out-noise the neighbours. Chinese newspapers report that people in Beijing are turning to vibrating motors, propped against the ceilings of their homes, to pump sound through the floors of people living loud upstairs.

Otherwise, the approach to combating noise is often to build thicker walls. In the UK, this has been precipitated by new energy-efficiency building regulations compelling homes to be highly insulated and more airtight to conserve heat in winter. It just so happens that these environmental measures cocoon rooms from outside sound. Two birds, one stone?

During hot spells, do you pay for cool silence or open your windows and let in the din? Air conditioning units hang outside apartments in Shenyang, China. Photograph: VCG via Getty Images

Not exactly. The same energy-efficiency measures that keep homes warm in the winter also trap heat in the summer, meaning people are spending more of the year with the windows open.

“In terms of health effects, this is particularly significant at night when residents are effectively left with a choice of being uncomfortably hot or having their sleep disturbed by noise,” says Dr Anthony Chilton, senior partner at the environmental engineering firm Max Fordham.

One solution would be to run air conditioning and keep the windows shut – but apart from undermining the environmental purpose of thicker insulation, this also introduces scope for social division. Do you pay for cool silence, or open your windows and live with the din? As Peabody’s Patrick Duffy notes: “You’ll have people who can afford to buy and run a cooling system. People in the equivalent flat next door may be social housing tenants and couldn’t afford that.”

Too quiet …

If you do manage to block the sounds of the city, there’s the risk you make things too quiet, too uncomfortably silent. Michael Jones, senior partner at Foster + Partners, says that as ventilation technology has improved, the low whizz and hum of fans has vanished. In modern open-plan offices the quieter the room gets, the further speech travels. In response it has become common practice to install “pink noise” speakers that emit a constant low fuzz of soothing static – essentially white noise with higher frequencies reduced.

Tailored to the frequency of the human voice, this barely audible whoosh masks background conversations. You don’t consciously notice it, but you do when it stops. “You’re suddenly aware of everything,” says Jones. “Every phone, every cough.”

When the software company Autodesk temporarily turned off the pink noise systems in its offices in Waltham, Massachusetts, staff complained about being distracted by conversations 20 metres away.

Harbour, who built a similar noise system into his designs for a business quarter in London’s Stratford City, describes it as like engineering a race car: starting with a design that is underweight, then calculatedly adding weight little by little. “If you cut the sound out, you can add noise so it feels right,” he says. “It can be tailored in a way that’s better for everyone.”

The interior of Bloomberg’s HQ in London uses Meyer Sound’s Constellation system to change the reverberation of spaces. Photograph: Alamy

Bloomberg’s European headquarters in London, which Jones worked on for Foster + Partners, uses Meyer Sound’s sophisticated Constellation electroacoustic system to change the reverberation of spaces, as well as pick up and isolate voices in vast, busy rooms.

Constellation has been described by the New Yorker as “the sonic equivalent of Photoshop”. Instead of pumping background static, it works by using microphones to capture the sound of a space, remodel it with digital systems, then send this acoustically improved edit out via a series of loudspeakers. Because this is all done digitally, sound can be changed on the fly, adding reverberation, or tweaking decay, strength, clarity and warmth. The company has described all this as “invisible architecture”, and while it has mainly been using it with concert halls and theatres, it is testing other uses, including in schools and restaurants.

“You can hear the clinking of glasses and the kitchen noise, and using the system we can zone that over your table,” says Helen Meyer, who founded Meyer Sound with her husband. “That means you can actually hear conversations around you kind of happening, but you can’t pick up the words. At your table, though, you can talk directly to the person.”

“As the technology becomes more accessible, I believe the next step will be to experiment with residential buildings,” adds her husband, John. “You could create whole new environments in your house, such as being in the woods. It’s really just programming.”

Being able to digitally edit the sound of your home to have the acoustic properties of a forest might be the future, but Constellation systems currently cost from hundreds of thousands of pounds to upwards of £2m. For the vast majority of people, those in inner-city areas tucked beside railways and main roads, this is simply an unaffordable solution. More likely for now are thick walls and indoor balconies, blocking noise without killing it completely.

Ultimately, though, sound can be a sign of life: from the chitter of children to the muffled voices from a neighbour’s TV. A clang and a clatter can cause a headache, but who wants to live in a city that sounds like a vacuum?

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