[Column] Risks of noise-induced hearing loss faced by many people today and how to avoid them

▲LOOPWhat's revolutionary about LOOP? It solves the change in sound quality (muffled sound) that occurs with volume suppression by mimicking the physical structure of the ear canal. The human ear is connected to the eardrum through a 25- to 30-mm long hole called the external auditory canal, but because it has a cylindrical shape with only one side open, air column resonance, known as open tube resonance, occurs. It's a physical phenomenon that causes peaks (high levels) and dips (low levels) at natural frequencies. However, it seems that the brain subconsciously compensates for it and senses it by subtracting that amount. There is no way to know that there are large peaks around 3kHz and 9kHz in everyday life. Such an ear, but if you plug the hole with earplugs, the physical characteristics will change from open-tube resonance to closed-tube resonance. In other words, because the specific frequency of resonance deviates greatly, the peaks and dips of open-tube resonance that had been secretly corrected until now suddenly disappear, and instead peaks and dips appear in different frequency bands due to closed-tube resonance. Perhaps the brain is confused with "Huh? Huh?". LOOP uses ear tips with high sound insulation to ensure silence while taking in external sound from the opening, but before it flows into the ear canal, it passes through a hollow channel that mimics the ear canal. In other words, the sound is delivered to the eardrum after generating the same peaks and dips as the original open tube resonance. This is the basic mechanism that allows us to perceive a sound that is the same as the original tone. I'm worried about the new peaks and dips caused by closed tube resonance, but since the sound in the outer ear is a small volume with a 20db sound insulation, the closed tube resonance generated from there is extremely small, and everything is masked. It will be gone. It is inevitable that LOOP has a cylindrical structure, but by using 3D printing technology to make it as compact as possible, it has a design that fits all ears, and it is as compact and fashionable as a piercing. It became an item with sexuality. The design does not protrude from the ear, so it is also good that it can be used without problems during sleep. After getting the LOOP and using it in various situations, I can feel that the sound itself is very clear and natural, with no stagnation, despite the light comfort and solid sound insulation performance. The fact that you forget you're even wearing it is largely due to the "natural sound quality" as well as the "good feeling of wearing". This is the decisive difference from general earplugs. Because it is not completely soundproof, you can enjoy music and conversations without any discomfort, and you will not miss any life alerts. Not only at live venues, but also at engine sounds, working sounds of electric tools, pachinko halls, karaoke, movie theaters, etc., you can get a different and safer sound reduction environment than usual. I don't want to. Freeing yourself from noise while traveling by air or train can create a very peaceful environment, and silence is just the thing when you need to concentrate. It's just earplugs, but the quietness and peace of mind that you get with just this one will give you a high-quality daily life that will make your life level go up a notch. "Quiet environment" can be said to be "the best luxury item" for busy modern people. Text: BARKS Editor-in-chief Tetsuya Karasuma ●LOOP 3,880 yen (tax included) now on sale ・Hearing protection earplugs designed for concerts, events, sports, travel and musicians ・Size: 1.5cm in diameter ・Weight: 2g ・Materials : ABS resin ・Accessories: Pouch, user guide, 6 pairs of ear tips (low-resilience foam: sizes S, M, L, silicone ear tips: sizes S, M, L) ・Color variations: Swinging silver / Raving red / Midnight Black / Glorious Gold / Flurty Rose Gold LOOP Official Site

* Mechanism of noise-induced hearing loss

Many hair cells of different lengths stand side by side in the cochlea, each responsible for each frequency. Loud noise is a strong stimulus for hair cells, and if they continue to be stimulated, they will collapse from exhaustion. When they are young, they recover by resting and stand up again, but that is only a matter of degree. This is the onset process of noise-induced hearing loss. The risk of noise-induced hearing loss varies depending not only on the volume but also on the duration of the load. Even if it is not very large, the longer the exposure time, the greater the risk. Conversely, at a high volume of 120 dB, 7 minutes is the limit. Noise-induced hearing loss is often damaged from 4KHz and 6KHz, and then the inaudible range spreads from 3KHz to 2KHz. Not only noise-induced hearing loss, but also presbycusis due to the passage of time does not damage all hair cells all at once, so it is difficult to notice the fact that a specific frequency cannot be heard. By the time you realize that something is wrong with your hearing, it will be too late and the damage will be widespread. There is also the “difficulty in ear care”. Even in complete darkness, your eyes get used to it and you can see the surroundings vaguely over time. This is dark adaptation, in which the dynamic range of vision is changed by the function of the brain. The phenomenon of not feeling big will occur. In that state, the music doesn't feel powerful, and you go into a spiral of increasing the volume, and before you know it, you don't realize that you're exposed to a volume that's so loud that it damages your auditory cells. Even in the concert, the volume gradually rises in the second half, but many audiences do not notice it. The solution to this problem is simple: just give your ears a rest. Turn off the music and take a break, even if it's just 10 minutes. If you reset the sensitivity of your ears and prepare earphones/headphones with high sound insulation, you can receive the rich amount of information that music has at a very low volume. If you increase the sensitivity of your hearing and broaden your dynamic range, you will be able to fully enjoy music even at low volumes. becomes. Tweet this article

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