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How to make your house and garden more tranquil – tips from an acoustics expert

<p>Many of us have been spending more time at home than ever before, and chances are unless you live by yourself in the middle of nowhere, at some point unwanted noise will have infiltrated your lockdown.</p> <p>Whether it’s cars passing nearby, a neighbour’s blaring music or the constant drone of a lawnmower, the trouble with sound is that – unlike light – it can be hard to block out completely. This is because it’s <a href="https://www.physicsclassroom.com/class/sound/u11l1c.cfm">a pressure wave</a> in air that readily diffracts around objects and easily passes through porous obstacles such as trees and shrubs. </p> <p>The wind and temperature gradient in the atmosphere also <a href="https://morgridge.org/blue-sky/how-do-temperature-and-wind-affect-traffic-noise/">affects transmission</a>of noise. This is why we may hear the noise from a distant motorway if the wind is blowing from that direction – or think the motorway has moved to the bottom of the garden on a cold still morning when there is a temperature inversion – this is when there are warmer layers of air above colder ones.</p> <p>Another issue with sound is that people living in a quiet area may be more seriously disturbed by the odd passing vehicle than people living in an area where traffic noise is more constant.</p> <div data-id="17"> </div> <h2>Creating quiet</h2> <p>Reducing noise at source is usually the best course of action. Ideally, many of us would like to reduce the number of noisy vehicles passing our homes and gardens but unfortunately, we can’t control this. In the case of road traffic, reducing the speed limit would help – as would a smoother road surface or, better still, a surface that absorbs sound such as porous asphalt. These are all jobs for the highway authority – but they may have more pressing claims on their budgets.</p> <p>There are, however, things you can do around your house and garden to make things a little more peaceful. A barrier such as a close boarded fence, earth mound or wall close to the road should help – but they will have to be long enough and high enough to have much effect.</p> <p>Much depends on where the house is in relation to the road. The aim would be to position any barrier so that the road is not in view from any exposed window or part of the garden.</p> <p>If noise can’t be controlled over the whole garden then consider making a tranquil zone in part of the garden where you can relax. This might involve building a wall or fence around part of the area to block the major sources of noise while not forgetting that the house itself can act as an effective barrier. </p> <p><a href="https://bradscholars.brad.ac.uk/handle/10454/11576">A water feature</a> may also help to mask residual noise. The more natural sounding this is the better – but make sure it’s not too noisy, as this may be disturbing to you or your neighbours.</p> <h2>Natural features</h2> <p>Interestingly our <a href="https://theconversation.com/how-tranquil-spaces-can-help-people-feel-calm-and-relaxed-in-cities-82358">perception of tranquillity</a> is shaped not only by the sounds we hear but also what we see. </p> <p>A study involving brain scans has shown that we process auditory information differently <a href="https://pubmed.ncbi.nlm.nih.gov/20600971/">depending on the scene in view</a>. The noise of a sandy beach and motorway at distance are quite similar, but research has shown that if using the same sound recording while showing a beach scene (as opposed to a motorway scene) to volunteers in an MRI scanner, the resulting brain patterns differ significantly. The rated tranquillity also differs significantly.</p> <p>In fact, <a href="https://www.researchgate.net/publication/273366914_Tranquillity_and_soundscapes_in_urban_green_spaces-predicted_and_actual_assessments_from_a_questionnaire_survey">research on tranquility has shown</a> that the rated tranquillity of a place depends on both the percentage of natural features – such as greenery, rock, sand and water – in view and the level of man-made noise. </p> <p>This means there is a trade-off in the sense that if you cannot control the noise, the perceived tranquillity improves if the amount of greenery or water in view increases. This is worth bearing in mind when creating a tranquil garden space.</p> <h2>Finding tranquillity indoors</h2> <p>Inside the home, some of the same principles apply. Reduce sources of noise by installing double glazing to windows and doors and add a thicker insulation layer in the loft to control aircraft noise.</p> <p>If it proves difficult to control noise in the bedroom then think about changing rooms so that you sleep on the non-traffic side of the house. Another thought is to include pictures of nature as wall art – the bigger the better – as <a href="https://core.ac.uk/display/76945458?source=2">research has shown</a> that installing pictures of nature scenes on the walls, as well as playing relaxing sea sounds as background music, can significantly improve people’s experiences of tranquillity and anxiety in a doctor’s waiting room.</p> <p>Many of us have enjoyed listening to the birds more often with the reduced traffic levels of lockdown. It would be nice to think the “new normal” would include some of these gains. Hopefully people will realise that many of the journeys they make by car are not strictly necessary. And it’s important not to forget that nature is around us all the time – if only we just take a moment to stop and listen.</p> <p><em>Image credits: Getty Images</em></p> <p><em>This article originally appeared on <a href="https://theconversation.com/how-to-make-your-house-and-garden-more-tranquil-tips-from-an-acoustics-expert-140208" target="_blank" rel="noopener">The Conversation</a>. </em></p>

Home & Garden

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The bizarre acoustics of Mars

<p>Shortly after NASA’s Mars Perseverance rover <a href="https://cosmosmagazine.com/space/perseverance-pays-off/" target="_blank" rel="noreferrer noopener">landed</a> and unlimbered its instruments, scientists turned on one of the more unusual of them – a microphone system – and for the first time listened in on an alien world: first to the wind, then to the sounds of the rover driving, and later yet to the <a href="https://cosmosmagazine.com/space/exploration/ingenuity-helicopter/" target="_blank" rel="noreferrer noopener">Ingenuity helicopter</a> on one of its early flights.</p> <p>It was captivating. But it also seemed to be of limited scientific value – the type of thing you’d do because today’s microphones are so lightweight that there’s no real cost to including a couple on the rover (and being able to listen to it might help diagnose mechanical problems if they arose).</p> <p>But it turns out there are a lot of other things you can do with microphones, once you have them.</p> <p>The simplest is to measure the speed of sound. On Earth, says Baptiste Chide, a postdoctoral researcher at Los Alamos National Laboratory, New Mexico, US, that’s about 340 metres per second. In the thin Martian air, it was expected to be more like 240 m/s.</p> <p><a href="https://mars.nasa.gov/mars2020/multimedia/audio/" target="_blank" rel="noreferrer noopener">Sounds on Mars</a> were also expected to be about 20 decibels lower than on Earth, Chide said at this year’s Lunar and Planetary Science Conference (LPSC) in The Woodlands, Texas. The Red Planet, he says, is also the “quiet planet.”</p> <p>The difference, he adds, is particularly pronounced at higher frequencies – something borne out by the muted sounds first released by NASA.</p> <figure class="wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio"> <div class="wp-block-embed__wrapper"> <div class="entry-content-asset"> <div class="embed-wrapper"> <div class="inner"><iframe title="NASA's Perseverance Rover Captures the Sounds of Mars" src="https://www.youtube.com/embed/GHenFGnixzU?feature=oembed" width="500" height="281" frameborder="0" allowfullscreen="allowfullscreen"></iframe></div> </div> </div> </div> </figure> <p>To a large extent, Chide says, “you can only hear bass sounds on Mars”.</p> <div class="newsletter-box"> <div id="wpcf7-f6-p185282-o1" class="wpcf7" dir="ltr" lang="en-US" role="form"> </div> </div> <p>Weirder yet, due to strange properties of its thin carbon dioxide atmosphere, sounds on Mars travel at different speeds depending on their frequency, with those above 400 hertz (about that of the G above middle C) travelling 4% faster than those of lower pitch.</p> <p>“Let’s imagine that we have this <a href="https://www.hou.usra.edu/meetings/lpsc2022/pdf/1357.pdf" target="_blank" rel="noreferrer noopener">talk</a> on Mars,” Chide said at the LPSC meeting. “My voice is between 200 hertz and 1000 hertz. You would receive all of the high-frequency tones before the low-frequency tones, so it might [be] distort[ed], not understandable.”</p> <p>But things like that are mere curiosities. The true scientific value of the microphones came into play when Chide’s team realised they could use them to measure rapid fluctuations in the air temperature in the vicinity of the rover.</p> <p>It works, he says, because air temperature is another factor that affects the speed of sound. And one way the rover produces sound is by firing its mast-mounted laser at nearby rocks.</p> <p>The primary purpose of the laser is to vaporise tiny puffs of rock so that other instruments can determine their composition from spectroscopic analysis of the escaping vapor.</p> <p>But the vaporisation process produces an audible pop when the laser hits the rock, and by timing how quickly that is heard after the laser is fired, Chide says, it’s possible to determine the temperature of the intervening air.</p> <p>That makes the microphone a useful complement to the rover’s onboard weather station, because it gives much more rapid readings, repeating each time a laser pulse is fired, which can be as often as three times a second.</p> <p><img id="cosmos-post-tracker" style="opacity: 0; height: 1px!important; width: 1px!important; border: 0!important; position: absolute!important; z-index: -1!important;" src="https://syndication.cosmosmagazine.com/?id=185282&amp;title=The+bizarre+acoustics+of+Mars" width="1" height="1" data-spai-target="src" data-spai-orig="" data-spai-exclude="nocdn" /></p> <div id="contributors"> <p><em><a href="https://cosmosmagazine.com/science/engineering/the-bizarre-acoustics-of-mars/" target="_blank" rel="noopener">This article</a> was originally published on <a href="https://cosmosmagazine.com" target="_blank" rel="noopener">Cosmos Magazine</a> and was written by <a href="https://cosmosmagazine.com/contributor/richard-a-lovett" target="_blank" rel="noopener">Richard A Lovett</a>. Richard A Lovett is a Portland, Oregon-based science writer and science fiction author. He is a frequent contributor to Cosmos.</em></p> <p><em>Image: NASA</em></p> </div>

Technology

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Inside the new “acoustically perfect” $400 million concert hall in London

<p>The first designs have been unveiled to provide a “world class concert hall” in the centre of London. The current site is a London roundabout, but there are plans to turn it into the Centre for Music.</p> <p>The Centre of Music will have a road running beneath it, as to not impact the flow of traffic. It’s being entirely funded by commercial backers and philanthropists and is looking to cost around £228 million (NZD$432 million).</p> <p>The London Symphony Orchestra couldn’t be more thrilled with the new designs and plans, as they have high hopes for the space.</p> <p>According to the London Symphony Orchestra website, the Centre includes a state-of-the-art concert hall as well as spaces for performance, education and rehearsal.</p> <p>The website goes onto explain:</p> <p>“It [the Centre] aims, above all, to be a place for people of all ages and backgrounds to experience the joy of music-making first hand. Aiming to create a new civic space that draws the public from all directions, and which hosts a mix of outdoor programmes and social spaces, the approach ensures the Centre would be a beehive of activity both day and night – creating a place where people want to spend time, even without a concert ticket.”</p> <p>Check out the gallery above to see the first designs. It’s set to be a stunner.</p>

Music

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