Heathrow airport has a new hi-tech weapon in its battle to win over public support for its long-desired third runway.

A small sound laboratory has been set up in central London offering a simulated taste of what a future expanded airport would sound like.

Inside, the listener sits surrounded by speakers at floor and ceiling levels, to get a 3D impression of a plane flying overhead, with images also screened. It can be precisely calibrated to time of day, distance from the airport, it can even simulate the effect of sound-insulated windows.

With the main factor influencing opposition to a third runway at Heathrow being potential aircraft noise – particularly for those who live beneath the prevailing west London flight paths – the simulator has been developed for politicians and local residents to test Heathrow’s claim that noise can be, at the very least, toned down.

The Arup Sound Lab, originally created by the engineering firm to help the acoustic design of buildings such as concert halls, was also used to allow residents living along the HS2 route to gauge potential disruption from high-speed trains, even though noise disturbance was a relatively minor concern for many HS2 opponents.

In contrast, aircraft noise around Heathrow can be all-encompassing, even conversation-stopping. It most directly affects the London borough of Hounslow, where at peak times planes land every 30 to 40 seconds.

Strong feelings against aircraft noise are just as likely to be found further away in more affluent areas such as Richmond than in Hounslow, which has very busy roads and plays host to the airport workers who are much more used to the noise.

Richard Greer, Arup’s director in charge of the acoustic programme, says that our perception of background noise is skewed because we rarely experience anything near true silence. Only minutes after I enter the lab, a soundproofed box room, does Greer draw my attention to the fact that a soundtrack is playing. With the soundtrack switched off, the silence is startling. Everyday life is depressingly loud once you realise what true silence sounds like.

Greer insists that although Heathrow is paying for the sound lab Arup’s neutrality is maintained because it is key to the engineering firm’s credibility – plus it is peer-reviewed and laboriously checked.

The sound lab’s technicians can replay combinations of aircraft types, times of day, and both present and future scenarios, simulated in two locations: one in Hounslow 1.8 miles east of the airport perimeter, another in Richmond, nearly seven miles away, but both under the flightpath of the southern runway. Matt Gorman, Heathrow’s sustainability director, says: “We want to give people a realistic and objective experience of what sound levels are like around Heathrow today and what they will be like in the future, to help inform the debate.”

So far, a lot of Heathrow’s pledges have had to be taken on trust - even if a new generation of quieter planes has started filling up slots at the airport. Allowing people to experience what the toned-down noise sounds like is clearly something the airport believes will help. “It’s not about telling you what to think, it’s about presenting information,” says Gorman.

Councillors, MPs and high-profile opponents such as John Stewart, of the anti-expansion group Hacan, who chaired the coalition of protesters against the previous third runway plan, have been invited in.

In Heathrow’s vision of the future, the airport will be a premium hub with the cleanest and quietest aircraft flocking to use it. Steeper landing approaches on the new runway will allow planes to fly higher for longer, disturbing fewer people in west London.

Gorman says Heathrow won’t need to ban noisier planes; they should be phased out within the next seven years – although a Heathrow noise action plan from 2011 promised they would be gone by 2015. But a measure of the airport’s new-found apparent intent to address the noise issue came in its vastly increased offer last month of up to £700m for measures to insulate local homes and public buildings.

Should the Airports Commission recommend expanding Heathrow, Arup expects to develop a more accessible public version of the lab It is keen for people to come in free of preconceptions, experience the lab for themselves and form their own judgments. But this is what the sound lab simulation suggested to me.

The Boeing 787 “Dreamliner”, for all the hype about its quieter engines, still makes a lot of noise – almost as much as the A320 in the simulation. The smaller A320’s whistling sound apparently grates on the ears of residents – but the 787’s reverberation is not insignificant either. Similarly, the giant A380 is far quieter than the hellish roar of a 747 flying overhead – but it is still a big plane, making noise.

Assuming Heathrow keeps all its pledges – and the Arup simulation is accurate – properly installed sound insulation, available to many under the compensation scheme, can vastly reduce the sound compared to standard double glazing, which might be assumed to cut out most noise.

Outdoors, when a plane is flying over, there’s little escape. However, the lab also showed that, if properly mitigated – indoors, with insulation, on a steeper approach – a 787 or A380 becomes barely audible when coming in to land on an alternate runway.

That suggests that any expansion plans must involve giving areas breaks from engine noise: more than anything else, the change of flight path will make a difference for those worst affected. The third runway (potentially) could alleviate it even more, if the pattern of respite can be sustained or guaranteed.

There are definite questions to be resolved and guarantees that many would seek: the real-life effectiveness of insulation and its geographical spread; the elimination of noisy planes; and exactly how to spread the pain once hundreds of thousands of extra flights a year from a new runway are factored in. And of course, some would definitely suffer more under the new flight path of that new runway.

But SoundLab appears to show that the noise problem is, if far from solved, something that can genuinely be moderated in future years.

Remarkably, John Stewart of Hacan – despite remaining firmly opposed to a third runway – seems to agree. “It’s a useful tool to show how quieter planes will impact on local communities. On noise grounds it makes the prospect of a third runway a little less of an issue: what this did show me is that the new generation of planes will be quite a lot quieter than the current planes in the sky.

“There is a residue of mistrust at Heathrow, but my belief is that they now understand and will deliver on whatever commitments they make regarding a third runway.

“The critical question is if they could prove a third runway would lead to more respite for communities than they get today. Then they may be on to a winner.”