This blog post examines the benefits of noise-canceling technology and discusses ways to address the resulting safety concerns and social disconnection.
Noise is defined as sensory pollution perceived through hearing. It is not merely sound heard by the ears but an environmental factor deeply impacting our daily lives. As cities develop and mechanized modern society rapidly expands, noise is becoming increasingly common around us. Noise originates from traffic, factories, and even various electronic devices within homes. What impact does noise from such diverse sources have on humans?
Noise affects the human body physiologically and psychologically, reducing work efficiency. For instance, prolonged exposure to noise can easily cause fatigue, reduced concentration, and even feelings of anxiety and stress. Long-term exposure to noise negatively impacts the heart and brain, increasing the risk of chronic conditions like hypertension and insomnia. Furthermore, stress induced by noise can affect the digestive system, including the stomach and intestines, and even impact the respiratory system. Thus, noise is not merely an unpleasant sound; it acts as a serious threat to our health.
Of course, noise with a consistent pattern, like the white noise found in reading rooms, can actually aid concentration. Such noise acts as background sound, reducing distractions and potentially enhancing focus. However, irregular and loud noise is different. Unnecessary and excessive noise appears to cause us significant harm. Unexpected loud noises, in particular, can rapidly increase heart rate, potentially triggering temporary fear or anxiety.
Noise cancellation refers to the technology that blocks or artificially eliminates unnecessary noise occurring in daily life. This technology has established itself as a crucial innovation for solving modern noise problems. Noise cancellation primarily reduces noise through two methods. First is passive elimination, which physically prevents external noise from reaching the ear. Examples include well-insulated headphones or in-ear earbuds that fit deeply into the ear canal. This method simply reduces noise through physical blocking, allowing the user to feel isolated from external sounds. The second method involves active noise cancellation, which electronically eliminates noise. The noise cancellation we typically expect or envision primarily refers to this second, active method. This is a more technologically advanced approach, analyzing ambient noise in real-time and generating counter-phase sound waves to effectively cancel it out.
When discussing noise-canceling technology, one of the most crucial elements is the microphone built into the earbuds or headphones. This relates to the principle of electronic noise cancellation mentioned earlier, which utilizes the effect of destructive interference. Destructive interference occurs when waves of opposite phases overlap, resulting in the amplitude of the combined wave becoming zero—meaning the sound becomes inaudible. In other words, if a sound wave with the opposite phase to the ambient noise waveform is generated, the noise level will be reduced to zero. Based on this principle, headphones listen to ambient noise through microphones and play the exact opposite sound wave to the user. This allows the user to hear less of the surrounding noise.
This active noise cancellation technology was first proposed and patented by Paul Greg in 1936. Later, in 1978, Dr. Amar Bose, founder of the global audio equipment company Bose, succeeded in developing the product. Eleven years later, in 1989, it was successfully commercialized, leading to the first release of aircraft-specific noise-canceling headphones designed for airline personnel suffering from noise-induced hearing loss due to jet engine and cabin noise. This innovation significantly reduced the discomfort caused by noise in daily life and provided auditory comfort to many.
However, as noise-canceling technology became widespread, new problems emerged. Noise-induced hearing loss saw a significant increase in patients alongside the popularization of earphone use. Incorrect use of earphones, which directly vibrate the eardrum, can cause noise-induced hearing loss. Experts have identified earphone usage duration and volume level as primary causes of noise-induced hearing loss. The longer the earphone usage time and the higher the volume, the greater the risk of exposure to noise-induced hearing loss. Therefore, maintaining appropriate volume levels and usage times is crucial when using earphones.
Noise-canceling technology offers greater benefits to users listening to music in highly noisy environments. Listening to music or videos in noisy environments often requires maintaining high volume levels. Elevated volume can cause noise-induced hearing loss. Noise-canceling technology addresses this issue by eliminating ambient noise, allowing sound to be heard at lower volumes. This prevents the high volume levels often cited as a cause of noise-induced hearing loss. Lower volume levels will restore some degree of ear health to earphone users. Leveraging this advantage of noise cancellation, in July 2019, Sony, a leading Japanese electronics company, advertised its noise-canceling earphones with the slogan “Lower the volume, lower your hearing age.” The reduced volume brought about by noise elimination will safeguard ear health, a point that seems indisputable.
Furthermore, noise-canceling technology is employed to create a better listening environment for the individual. Indeed, reviews of noise-canceling earphones frequently praise their ability to provide an excellent listening experience. Apple’s AirPods Pro even demonstrate such advanced noise cancellation that they eliminate the thumping sound in your ears when walking while wearing them. Some users describe it as feeling like floating in space. The effectiveness of noise-canceling technology available on the market is known to reach 90-99%. This is sufficient to reduce the noise of fighter jets taking off and landing to the level of rustling leaves, offering a clear advantage in creating an environment conducive to focusing on music.
However, experts note that current noise-canceling technology is not perfect. This is because the technology cannot completely eliminate noise across all frequency ranges. This is referred to as selective frequency cancellation. It is known that sounds in the ultra-low frequency range and high-frequency sounds above 1300Hz cannot be eliminated. This means that while most sounds in the world can be removed, some remain. So, what effect do these remaining, unremoved sounds have? If noise-canceling technology eliminates low, mid, and high-frequency sounds, the ultra-low frequencies are not removed and reach the ear. Consequently, ultra-low-frequency sounds, which are not typically heard loudly, become relatively louder. These amplified ultra-low-frequency sounds can create a sensation of pressure, similar to what one feels in high-rise buildings, and may even cause motion sickness in sensitive individuals. Current noise-canceling technology has this technical limitation.
Noise-canceling technology isn’t just about technical issues. It can also pose safety risks to users. We’ve all experienced walking down an alley listening to music, only to be startled by a car horn because we didn’t hear it approaching. Using earphones while walking can cause a lack of awareness, potentially contributing to an increase in pedestrian accidents. In fact, this issue is one of the concerns that arose alongside the development of electronic devices and the widespread adoption of earphones.
This problem appears likely to be exacerbated by noise-canceling earphones, which eliminate ambient noise. This is because sounds that were previously audible are now blocked by noise-canceling technology, further reducing awareness. Of course, manufacturers also include a feature that allows ambient sounds to be heard through microphones. Using this feature allows one to hear sounds as if not wearing earphones. However, this feature is unlikely to significantly reduce accidents. If users consistently walk around with the ambient sound feature activated near roads, this problem might be solved. However, turning off noise-canceling technology in high-traffic environments to hear ambient sounds directly negates the benefits of the technology itself, and users likely wouldn’t want to hear the noise of cars either. Accidents can occur unexpectedly anywhere, and it seems impossible to switch off noise cancellation just as an accident is about to happen while driving with noise blocked. Regulations for the safety of pedestrians and noise-canceling earphone users appear necessary to some extent.
Aristotle stated, “Man is a political animal.” Humans exist as individuals, yet they constantly exist within relationships with others. He saw the execution of good deeds through communication and coordination within these relationships as something only humans could achieve. However, contemporary society seems to be moving in the opposite direction of Aristotle’s words, and this aspect is increasingly discussed as a significant social issue. Excessive individualization is occurring. We’ve recently encountered new terms like ‘solo dining’ and ‘solo drinking’. This is because eating alone, watching movies alone, and drinking alone have become comfortable. Eating alone eliminates the need to debate over multiple menu choices, and it offers an even greater advantage when selecting movies, where tastes diverge widely. Interacting and coordinating with others now seems to be viewed as a bothersome chore.
The rise of earbuds has sparked significant concern regarding this disconnect in communication. Plugging in earbuds and staring at a phone anywhere allows one to temporarily disconnect from society. The advent of noise-canceling technology, which blocks out all external sounds, will have an even greater impact than the effects of earbuds alone. From the moment one puts on noise-canceling earbuds, they cannot hear another person until that person taps their shoulder; communication becomes possible only through mobile devices. The constant interaction with others that occurs within society is significantly interrupted when noise-canceling is active. This could lead to a situation where technology limits the unique human ability—distinct from other living beings—of maintaining constant social exchange.
Another issue shares the context of Plato’s “Phaedrus” and the “Judgment of King Thamus.” Technology developed for human convenience can instead limit human capabilities. One advantage of noise-canceling earphones is providing a better listening environment. That is, by providing a quiet environment, they allow users to hear only the inherent sound when listening to music or watching videos. Users of noise-canceling earphones consistently report that external noise is blocked, making it easier to concentrate on any task or reading. This offers a significant advantage for tasks demanding high concentration, like studying. However, problems arise when users become accustomed to this. The quiet environment noise cancellation provides is an exceptionally special one that doesn’t exist in the real world. Users can focus entirely on a single piece of music, a single video, or whatever task they’re doing without any extra effort. Just as some people find it hard to concentrate on work without coffee, known as a stimulant, noise cancellation can also cause a decline in concentration in normal environments where noise exists.
Noise-canceling technology is currently evolving beyond earbuds and headphones to be applied throughout living spaces like homes and cars. This signifies that the scope of noise blocking will continue to expand. As noise-canceling technology advances and its applications broaden, we will live in environments with less noise. However, the issues of social disconnection and diminished concentration discussed earlier may arise not just with earphones, but across our entire lives.
While the noise reduction effect is significant, we must also thoroughly consider potential safety issues, social problems, and the decline in human capabilities. Before noise-canceling technology advances and is applied to various areas of human life, I believe we need to deeply contemplate and fully consider these issues.
