• Sound Scrubbing

    Noise. A straight-forward term, but one that is tricky to peg down to a few broad based meanings.

    The loud door bell, thunder, telephone ringing, TV volume on high, a resounding sneeze, kids yelling in high decibels, monotonous snoring, a dog barking, a beginner practicing violin…the list seems endless.

    Those are the decisively loud ones. But certain other sounds such as wind chimes tingling, loud music, water dripping from a tap, canary birds twittering at a neighbours house, etc will fall under the category of being noise to a listeners’ ears. Because one man’s music could well be another man’s noise.

    But there is the one category of noise that is universally a disturbing one. The incessant sound of traffic.
    How do we combat this problem then? “Try sound scrubbing,” says Dinesh Ethiraj.

    What Is Sound Scrubbing?

    It is nothing other than masking (at best reducing its loudness) your surrounding from any bothersome noise by placing sound barriers.
    When a residential community comes up next to a busy highway, the common method adopted in Western countries is to build a noise barrier wall around the apartment complex. Even if it does not achieve a 100 percent success rate, results from polls conducted amongst residents state that the advantages of the barrier wall override the disadvantages and that the overall quality of life is improved.

    Starting with the basic that most noise begin at pavement level (tire on asphalt), and then take into account the blaring honking, what is the best line of defense?

    Planting Reinforcements

    So how do we apply the sound scrubbing concept in the urban setting that we presently live in?

    Time to call in reinforcements to tackle this source of pollution. While surfing the net to consider small scale sound barrier possibilities, we came across Kenneth Freeman’s work on this exact line.

    He has recorded extensive study on the impressive multi-tasking abilities of the indoor potted plants. Titled Plants in “Green Buildings” it is presented under the aegises of Ambius White Paper. If interested check out the following link:


    As wonderful as they look, the interior potted plants serve a versatile purpose.

    Freeman even goes on to say, “One other important benefit is their ability to reduce noise levels in buildings, reducing the need for expensive (and often ugly) manufactured acoustic panels.”

    Really? How so, one may well wonder. According to Freeman, research shows that plant displays are effective at absorbing, diffracting and reflecting sound. “As well as absorption, plants affect room acoustics by diffraction and reflection, particularly at lower frequencies. This works because the leaf size of indoor plants is small by comparison to the wavelength of the noise. Plants with lots of small leaves are useful as they scatter and diffuse sound. At higher frequencies the leaves may reflect sound towards other surfaces that may then absorb the noise.”

    “So, how can you practically use plants to reduce noise? First, use large plant containers. These pack in more compost and have a greater area of top dressing, both of which have a significant effect on noise reduction in their own right, so it follows that they make a larger impact on the room acoustics. It will also be possible to get larger plants, or several plants into the container as well.”

    “Secondly, use a mixture of different plant species and sizes. Experiments have shown that arrangements of different plants in groups appear to work better than individual plants and that several small arrangements are better than one big one.”

    Sound can actually be masked then? Sounds too good to be true? Can Freeman’s findings be used to our advantage? And that too in the Indian urban context where there are no traffic rules. And where multi-storied buildings keep mushrooming by the road side, with hardly any pavement space between the compound wall or fence and the road?

    What People Think Of Noise Barriers

    When we introduced the concept of noise masking to a few people, we came back with very interesting responses. Most were skeptical to the thought that the presence of a few potted plants, or a landscaped terrace will tone down the volume of unwarranted conversation/fights floating from the neighbour’s house, or traffic noise coming from street. “We fix this invasion with the marvellous invention called windows. We shut them,” was their response. Also considering the narrow, if it is there at all, gap between two buildings, or the building and the street itself, “Where then is the scope to place pots or plant any thing?” they posed.

    Others oscillated between being intrigued to actually be willing to try the proposition for themselves.

    Eco-centric Approach

    Dinesh, who adopts an eco-centric approach as and when possible while implementing his various architectural projects, suggests that whether or not there is a physical reduction in noise levels, trees and other leafy vegetation do offer psychological relief.

    Prod him to elaborate his pet project, which is to include more elements towards increasing the green beltway in our community, he says, “It is high time we consider how the continuous levels of sounds from the streets will impact the people by stressing us out. And fortunately there are many eco-friendly ways to de-stress ourselves. Planting large leafy trees and plants around apartment complexes do act as sound barriers. Water sheets also, when provided along the noisy areas, help absorb and reduce their decibel levels. So if the greenery and ponds or fountains are going to serve a two-fold purpose, (i.e) make the landscape look greener as well as help filter sounds levels, why not go for it?” advocates Dinesh.

    “Look around your apartment premises. Any decent amount of space along the fencing area will do too,” he reassures. “Bamboo shoots and a few other leafy variety plants and small trees do not need much maintenance. Plant them. Even if you don’t reap any visible immediate relief in the first few months, give it a year’s time and you’ll be a true blue propagator for increasing the green coverage in the city scape,” he says with conviction.

    Regarding the incessant honking, Dinesh recommends maintaining lane discipline, which can help the commuter avoid using horns. “If generators, our staple electricity suppliers, are provided with silencers, then the hum from it will be reduced. Further more, city planners can install sound absorbers on the medians and footpaths to insulate street level sounds, which will be of immense help to institutions such as hospitals, schools etc,” he proposes as he hints at other proactive methods to tackle the noise pollution issue.

    Noise prevention is a difficult topic to dwell on, isn’t it? How many of you, dear readers, will vote for it when we say, within the margin of safety, that the only way to reduce the levels of road traffic noise is with the help of sound scrubbers and noise maskers? And that like how a closed window muffles traffic noise, so too do the scrubbers?

    Feel free to think about and discuss it with friends, neighbours, relatives, colleagues etc. If you do decide to implement a few of the above mentioned ideas (or custom make it to your requirements), we’d love to hear your experiences.