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From Issue #49 August 14, 2014

What Cost, Silence

A young man has an idea that pairs recycling with soundproofing.

By Dinsa Sachan Twitter icon 

A few months ago, when New Delhi wasn’t smoldering hot, 19-year-old Aditya Bali sported a long, flowing mane complemented by an immaculate French beard, to go with his obsession for underground music. 

He is a drummer for IV, a New Delhi band. It’s one of the many hats Bali wears, and the one that led him directly into his current academic and inventing career. Now a second-year engineering student, Bali loves the science and practice of recycling. Since 2012, he’s been consumed with an ecological quest, one that could dramatically reduce the cost of soundproofing rooms and buildings. If only he had time to pursue it.

A lack of silence in the library

At St. Mary’s School in Dwarka, New Delhi, Bali used his “head boy” status to access the school’s music studio outside its designated practice hours. His justification? The school was gearing up to perform a musical for its Annual Day in November 2012, and Bali, the school drummer, couldn’t get enough permitted time in the music room.

But his act of “stealth” didn’t last long. The music room was near the library, which was in constant use by one class or another during the school day. The cacophony of guitars, drums, and bass, played by Bali and fellow musicians, couldn’t be confined to their practice space. Constant complaints from the librarian culminated in a warning from the principal: “You’ve got to do something about the noise; this can’t go on.”

Quotes from soundproofing companies were Bali’s first reality check and elicited another scolding from the principal. “If we were going to do it using conventional methods, it would cost a bomb – around Rs. 1 lac [about $1,600 today]. The school didn’t have that kind of money,” Bali recollects.

But he was well placed to find an affordable alternative. St. Mary’s has an environmental mission that includes maintaining a sprawling “urban forest” comprising 32 indigenous plant species; it also diligently harvests rain water. As part of a joint initiative between food packaging firm Tetra Pak and TERI University, an institution specializing in sustainable development, St. Mary’s and other schools were involved in collecting used and thrown-away Tetra Pak cartons.

“The trash agent had not turned up in a long time,” Bali says. “And the cartons were lying unused in the campus.” This gave him an idea. The school’s Eco Club collected the cartons, and the club was spearheaded and founded by Seema Bali, the school’s vice principal — conveniently both Bali’s mother and his biology teacher.

“During brainstorming in biology class, we tried to connect our need — soundproofing [a] room — with the trash,” Bali says. Bali conducted initial experiments at home by filling an iron container with cartons. He knew he was onto something, but it was clear that cartons alone wouldn’t cut it.

Even though by then the pressure was mounting to study for his board examinations, which were instrumental for college admissions, Bali kept devoting time to his eco quest. It was easy for him to stifle family and school complaints: he had a compulsory biology project that year, and Bali’s unnamed labor of love became that project.

Can you hear me now?

Bali had many hits and misses as he developed the project. His first, rather comical gaffe: using cotton. “Cotton seemed to be a good fit. It is derived from plant source, made of cellulose, and has a lot of air pockets for noise absorption,” he says. He filled cartons with cotton and plastered them on the wall. It rained the next day, and the Tetra Paks fell to the ground. “Perhaps cotton absorbed moisture, making Tetra Paks really heavy.”

Team Bali finally homed in on sawdust. ”It’s an environment menace, so it made sense to confine it to cartons,” Bali says. But this solution had its own bug: sawdust, derived as it is from wood, attracts termites. Inserting leaves of the neem plant, a natural insect repellent, deterred the termites.

While the Eco Club installed around 9,000 sawdust-filled cartons in the studio, Bali managed to capture the attention of the Initiative for Research & Innovation in Science (IRIS) 2012, a science fair organized by India’s Department of Science and Technology, the Confederation of Indian Industries, and Intel Education.

To create a control case necessary for his entry, Bali used a wooden plank to divide the part of the studio that was laden with cartons from a smaller portion that wasn’t. Using audio software, he tested noise levels in the smaller portion, first without cartons and then with them. “The echo had almost vanished,” he says. The noise level inside was considerably reduced, by around 3 decibels (dB).

That sounds modest, but the decibel scale is logarithmic: a 3 dB reduction means a 50 percent drop in the audio energy emitted, and about a 20 percent lower perceived volume. Rufus, St. Mary’s music teacher (he prefers to use just his first name), says he estimates a roughly 60 percent reduction in the noise heard outside the studio.1

Although Bali didn’t win a ticket to the United States for the Intel International Science and Engineering Fair, he impressed the Indian environment ministry with his work, and grabbed a special award in environment management.

The best was yet to come, though: a scholarship in February 2013 of Rs 50,000 (about $800) from Swechha, a New Delhi nonprofit, to replicate his work in the school’s noisy photocopy room. Sunny Verma, deputy director at Swechha, mentored Bali during the fellowship, visited the school several times, and oversaw the soundproofing of the photocopy room. He says, “I could tell you that there was a very noticeable difference in the noise levels in that room.”

Quiet, please

Bali believes the low cost of his idea gives it a broad potential. “If put to commercial use, the technology could help soundproof small auditoriums, printing presses, generator rooms, and band practice rooms, etcetera,” Bali says. “It can really help startups who are cash-strapped.”

Verma believes that Bali has a “blockbuster” idea. “Though it might need refinement if it has to succeed commercially,” he says. A funky carton-laid studio can work for a school, but professionals may demand something more aesthetically pleasing.

Until about two months ago, Bali was ecstatic about taking his idea forward. He had applied for a patent for the technology, and planned to make a documentary to promote it. “I’m going to compose all the music for it,” an elated Bali had said.

But the grander plans have taken a backseat for the moment, as Bali copes with the pressure at college and a recent change to the grading system at his institute, Amity University in Noida, outside New Delhi. But he may have already spurred a local revolution.

Schools in St. Mary’s vicinity are embracing his idea, and Bali’s use of Tetra Paks triggered a new intensity in his own school. “Students are crazy about collecting Tetra Paks,” Seema Bali says. And everyone has a cute story of how they surmounted odds to retrieve packaging. “A little boy felt triumphant for having dodged a stubborn dog to collect the cartons from his community bin,” she recounts.

In the meantime, Bali has chopped his hair off, partly because of the heat and partly because he lacks the time to tend to his locks as he focuses on his studies and his future. The nifty side fringe that remains is a reminder of his “rock star” days and of a project still in progress.

Photos by the author.

  1. Like all point-source emitted energy, audio power drops off rapidly the farther one is from the source, so the variance can be high depending on one’s relative position. 

Freelance journalist Dinsa Sachan writes about science, tech, and culture from New Delhi, India.

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