In this blog post, we’ll explore how to control car noise and, furthermore, how to transform unpleasant sounds into “pleasant sounds.”
“Vroom, vroom”—when walking along the roadside, it’s easy to find yourself frowning at the noise emitted by countless cars. It’s so bad that on busy roads, it can even be difficult to have a conversation with the person next to you. This noise goes beyond mere inconvenience; it causes psychological stress and has a negative impact on health. Research shows that exposure to excessively high noise levels can lead not only to hearing loss but also to cardiovascular disease and sleep disorders. In major cities, in particular, persistent noise pollution is cited as a key factor that lowers people’s quality of life. Consequently, the issue of noise is emerging as a serious problem that must be addressed not merely as a daily inconvenience, but from a social and public health perspective.
Even when riding in a car, noise remains a significant issue. Noise heard inside the vehicle irritates passengers’ ears, causing fatigue and making them more irritable, which reduces concentration while driving. In particular, during long drives, such noise accelerates the accumulation of fatigue, thereby increasing the risk of accidents. For this reason, controlling vehicle noise has become a key factor in determining a car’s comfort. Socially, noise emission levels are regulated to minimize the harm caused by noise. Automakers are researching and developing various methods for noise control and adopting these technologies to provide consumers with a better driving environment. So, let’s explore the methods currently used to control vehicle noise.
Imagine loud music playing in a corner of a room. Assuming there are no barriers between the speaker and me, the loud sound would reach my ears directly and be painful to hear. How can we avoid this noise? One method is to surround the speaker with thick walls. The thick walls act as a barrier between the speaker and me, causing the loud music to sound much quieter. Next, we can generate another sound that cancels out the loud noise to eliminate it. Sound consists of various waves with specific frequencies and phases. Therefore, we can cancel it out by superimposing a sound with the same frequency but an opposite phase—that is, a sound with an opposite phase. The final method is very simple: just turn down the volume of the music coming from the speaker.
The same applies to noise generated by a car. Car noise is generally produced by the running engine or by friction between the tires and the road surface, or between the body and the air. If a car had no components other than the body, engine, and tires, the loud noise would enter the interior directly and interfere with driving. To block this noise, the body is first surrounded by walls made of sound-absorbing and sound-insulating materials. These walls absorb, reflect, or block the noise generated by the vehicle, making it sound much quieter. Automakers are constantly advancing these technologies, and particularly in luxury vehicles, they apply more sophisticated sound-absorbing and sound-insulating technologies to provide a quieter and more comfortable interior environment.
Next, there is an active noise control method that cancels out the noise heard inside the vehicle. Microphones are installed inside the vehicle to directly measure the noise, and sounds with the opposite phase are generated through speakers to cancel out the noise. This technology is particularly useful in large vehicles or electric vehicles where noise levels are high. Finally, through research and development, components that generate noise are replaced with ones that produce less noise by changing their materials or shapes. For example, changing the tread pattern on tires to a different design can reduce noise.
