The Masked Frequencies
Category Winner | Article
Author: Keerthi Sudarsan
Season 6

“When we are awakened participants within the processes of the network, we can start to hear what is coherent, what is broken, what is beautiful, and what is good”. David George Haskell

For a long time, I assumed I was overly sensitive to external stimuli, especially sound. The mere act of hearing a specific sound shifted my mood for better or for worse. To soothe my nerves, I found myself either plugged into my headphones listening to LOFI beats and podcasts or hooked onto changing my desktop wallpapers rigorously to green landscapes. Even in my social spaces, I gently gravitated towards a tranquil environment. Be it a quiet nook at the office, corner seats in a coffee shop, or an isolated table at a restaurant. Contrastingly, as I walked through the serene forest surrounded by natural sounds, I felt a positive shift in my personality and mood. Multiple visits to the forests made me realize I did not shun myself away from sounds but from over-accustomed anthropogenic noise. It made me wonder when I stopped being wary of this human cacophony.

Nevertheless, I observe my surroundings visually through sketching, painting, and photography. Vibrant green canopy, coarse brown barks, soft lavender sunset sky, crimson-yellow sunrise, deep blue ocean, and many more adjectives naturally roll my tongue to describe my visual perceptions. Life forms still transpire regardless of one’s perception. Don’t you agree? And that being said, have you tried observing nature through other senses? On one Tuesday morning around 9:30 am, I consciously decided to do this solely using my listening skills. The results were thought-provoking. Getting past the whizz of my ceiling fan, I could hear the tires of a van scraping the gravel road. It screeched at a decibel that physically made my face scrunch. A few seconds later, a brash two-wheeler followed the van, honking out its heart content. And in the background, the dooming noise of the water motor wrapped the entire sound spectrum. Finally, in the distance, I found solace perforating through this chaos. I heard yellow-billed babblers and Black Drongo chattering away, oriental magpie-robin singing over my window as the wind rustled through the leaves. It was fascinating how I could picture my environment with those subtle acoustic cues. Engaging in this exercise eventually turned into a habit, which later developed into one of my research interests that I am passionate about. I suppose, it is right to say that voices of every kind and form matter.

Though sound has been integral to species’ survival, sonic communication took a long time to evolve. A study on the evolution of acoustic communication transports us 350 million years back to our land-living vertebrate ancestors, tetrapods. Fascinatingly, their communication involved gestures rather than vocalizations. Before tetrapods, communication among organisms occurred only through vibrations. Merely around 100-200 million years ago, mammals, birds, frogs, and crocodilians evolved acoustically, independent from each other. Their nocturnal lifestyle has been strongly associated with the incidence of their sonic communication. It’s fascinating how I can undoubtedly imagine the scenario of this transition. The thread of DNA probably remembers. Picture yourself walking into a forest, where the daylight dips into the earth as the dense cold air knits the night together. Surrounding you are other terrestrial species lacking the ability to perceive visual cues in darkness. What could make sense as an alternative means of communication? You guessed it right, SOUND.

As innumerable scientific studies on the physiology of animal sounds ensued, researchers took a step further to understand the relationship between non-human animals, humans, and their sonic environment. It gave birth to soundscapes, a term used by Dr. Michael Southworth in 1969. He defines it as a collection of sounds that occur in an area at a particular time. Since then, there has been a steep incline towards acoustic studies. One notable individual in this field of research whose work I deeply admire is the famous soundscape ecologist and musician Dr. Bernie Krause. For over 40 years, he has been passionate about recording and preserving wild natural soundscapes.

In the early 1980s, a revelation occurred to him while listening to the sounds around a waterhole in Africa, which he elaborates on in his book, “The Great Animal Orchestra”. Resting in his tent, the sonic chorus of insects, distant lions, African wood owls, and several other animal vocalizations reminded him of Mozart’s elegantly structured Symphony No. 41 in C Major, K. 551. Subsequently, he realized that cataloguing and reviewing single-species acoustics from a whole acoustic bandwidth felt ‘like taking apart a Beethoven symphony and just examining the strings lines or the horn line’. Even Tobias Fischer reiterates this de-contextualization in the first anthology of animal music and collection, “Animal Music” in an interview with Dr. Krause.

In 2016, a London-based art studio, United Visual Arts (UVA), collaborated with Dr. Krause to create ‘The Great Animal Orchestra’, an hour-long visual translation of his recorded soundscapes from forests to oceans. Audio recordings, coupled with visual spectrograms, capture a transcendence symphony that flows between biophony (collective soundscape created by individual non-human organisms within a specific habitat) and geophony (sounds produced by non-biological elements like wind and water, and geological processes). Listening to this immersive collection, I felt a chill travel each second down my spine. I could wholly immerse myself in the omnipresence of life around and within me through every note of high- and low-frequency coos, caws, moos, creaks, and many more. Each note resonated with the tale of acoustic evolution nearly discernible to my existence.

The symphony certainly made me ponder how all those intricate weaves of signals from vocal species co-exist in one acoustic environment at the same time. Ecoacoustics aims to investigate this ecological role of sounds of geological, biophonic, and anthropogenic origin. Soundscape ecologists explain this co-existence using the acoustic niche hypothesis (ANH). In simpler terms, a vocal species can adjust its frequency range of a signal or the timing of its calls to reduce overlap with those of other calling species. Research shows, insects (3-4kHz or 6-8kHz) and ultra-sonic bats (>20kHz) occupy higher frequencies. Below this spectrum are the varied species of birds (2-12kHz), frogs and toads (2-5kHz), and further down in the low-frequency spectrum are the sounds of mammals, ranging from cats to elephants. The latter is also where most of the anthropogenic noise distillates (<4kHz).

How systematic! Yet, a thought deeply bothered me. If every vocal species evolved to communicate within its partitioned bandwidth, won’t anthrophonic noises interfere with their signals? Apparently, scientists say it very much does interfere. Primarily, birds can adapt by calling at higher frequencies, up to 400 hertz, and are even spectrally seen to lengthen their call duration. But not without an acoustic threshold. When they cross this threshold, their survival is threatened by an impact on their ability to safeguard their territory and attract a potential mate. Studies also show that low-flying planes can disrupt the synchronic calls of frogs, passing ships and sonar deter marine mammal communication, and busy roads, industrial areas, or noisy recreational activities can affect foraging in some terrestrial mammals.

We, as humans, aren’t immune from the effects of noise either. WHO has documented seven categories of health effects of noise on humans, i.e., hearing impairment, negative social behaviour, annoyance, interference with normal speech abilities, sleep disturbances, cardiovascular disease, and disruption in mental and physical health. The de-stress zones like retreat inns, nature parks, and beach resorts, they all seem to have one thing in common – a green space where noise is minimal. However, 20 years back, similar spaces were quite accessible in most of my neighbourhood. It was either a park or an empty ground that embodied massive mango, neem, and Acacia trees swishing winds on sweaty backs. It sure was a cost-efficient experience to enjoy nature. Although now, relishing natural landscapes comes with a price tag. Unfortunately, we have come to an age greenness also screams social disparity.

At present, I witness that urbanization and economic development are inevitable. I understand the necessity of convenient metro trains, employable IT parks, and freight transportable 4-lane roadways, extending railways and airways. Regardless, I fail to understand the disappearing sparrows, declining dragonflies, endangered wildlife, and barren lands. And among these two renditions, I see a connectivity. Even better or probably worse, now I even hear it. As Rachel Carson quotes in her book “Silent spring”, “nature has introduced great variety into the landscape, but man has displayed a passion simplifying it. Thus for, he undoes the built-in checks and balances by which it holds the species within bounds”. I ardently believe that a silent landscape is a harbinger of a total ecosystem collapse. Therefore, on a Tuesday morning, we can try listening to those acoustic cues of nature that quite loudly are screaming at us, in silence, under our anthrophonic masks. Perhaps, we can make the world a better place to listen and accordingly respond.

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