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  • William Robertson

What Are Decibels? A Guide To How Sound Is Measured

Although people may be familiar with the word, many still wonder, “What are decibels?” In this article, we will explore the history of this unit of measurement, how it differs from other ways we measure sound, and its purposes in medicine. By the end, you will walk away with a deeper understanding of this incredibly useful unit of measurement. It may forever change the way you experience sound.


Even when you are in a quiet room, there is a good chance you can still register some noise. The gentle hum of the air conditioning, the rumble of cars outside, or maybe the calls of animals in the distance—the world is a noisy place.

But not all sounds are the same. Throughout the natural world, we see areas of high noise intensity, like a lion’s roar, and low intensity, like a mosquito’s buzz. And as is the case with every other part of the natural world, people have tried to quantify and categorize the intensity of sound. From this endeavor, we now have decibels (dB), a unit of measurement for sound strength. In this article, we will explore the question: what are decibels?


Decibels were given their name to honor Alexander Graham Bell, the man who invented the telephone and the audiometer. An audiometer is a machine that determines a person’s ability to hear certain sounds. We still use a version of these devices today to help with diagnosing hearing loss.

Ways To Measure Sound

Decibels measure sound intensity, but there is another way to measure sound. Since sound is an energy that travels in waves, one can measure its frequency. Frequency, which is measured using the unit Hertz (Hz), is made up of the number of sound vibrations in one second. Meanwhile, you use decibels to account for a sound’s amplitude, which is its forcefulness or pressure on the decibel scale. With more amplitude comes a louder sound.

Linear vs. Logarithmic

Decibels are measured using a logarithmic scale, which is different from the commonly-used linear scale. For linear scales, the measure between two points will never change. Three inches is two inches more than one, and one inch is four fewer than five. Logarithmic scales, however, measure percent changes.

For instance, each 10 dB increase on the decibel scale is a 10-fold sound pressure level (SPL) increase. Close to silence is about 0 dB, 10 dB is 10 times louder than 0, and 20 dB is 100 times louder than near silence.

How Decibels Relate To Hearing Loss

Decibels are immensely valuable for measuring the harmful effects of loud noises on hearing loss. When people lose their hearing as a result of long-time exposure to loud noises or single exposure to a very loud noise, they experience what is known as noise-induced hearing loss (NIHL).

Scientists study the impact of NIHL and, according to the levels of noise in our world, create recommendations for safe listening. They endeavor to answer the question, “How loud is too loud?” Unsurprisingly, the louder the noise, the less amount of time scientists recommend you expose yourself to it. Exposure to noises louder than 85 dB for more than eight hours a day can scar a person’s hearing forever. It is helpful to know the measure of common sounds so you can prepare for instances when you might put your hearing at risk. Some examples include:

  • Conversation – 60 dB

  • Dense traffic – 85 dB

  • Lawnmower – 90 dB

  • Maximum volume for an MP3 player – 105 dB

  • Concerts and sirens – 120 dB

  • Guns – 150 dB

How To Prevent Hearing Loss

Thankfully, we are not all doomed to lose our hearing just because we drive through traffic or check out the occasional concert. Medical professionals tell us that we can protect our hearing if we take appropriate, intelligent safety precautions. If you are going to a loud club, woodworking, or riding a motorcycle, you can avoid damaging your ears by leveraging the following techniques.

  • Earplugs are available at most drug stores for very little money. The disposable ones are made of foam, while silicone earplugs can be washed and reused.

  • Custom ear molds are common items for musicians and hobbyists. Contact a hearing professional to order these.

  • Earmuffs that entirely cover the ear are excellent for keeping out noise. People can find them easily in sporting goods stores.

  • Noise-canceling headsets can muffle or entirely block out noise. They are often used by pilots and military personnel.

What Decibels Mean for Those With Hearing Loss

Even people who have not been diagnosed with hearing loss should be cognizant of the decibel levels around them. They should be concerned with protecting the hearing they have, even if it has been tarnished. People with mild hearing loss must conserve what they have by wearing the appropriate protective equipment. Untreated hearing loss can lead to other health complications, such as a greater risk for depression and dementia. All people should be proactive in conserving their hearing. When it is gone, it is difficult to get back.

As for people who already use hearing aids, they must be especially mindful of the dB levels in their lives. Hearing aids actually amplify sounds; as such, people who use hearing aids are equally as sensitive to NIHL as everyone else. Some people with hearing aids like to turn them off when it is too loud. However, hearing aids will not be able to block out the harmful noise, meaning people who do this might just prevent themselves from hearing important sounds.


Sound is literally all around us. Every time you walk down the street, turn on the radio, or run the faucet, a new symphony of noises comes crashing down around you. In this article, you learned a new way to rate and categorize those sounds. Using decibels, we can judge exactly how intense one sound is compared to others. For people struggling with hearing loss, decibels offer a clear guide of what levels of sound intensity to avoid. For people with healthy hearing, it is still advisable to understand the different decibel levels of sounds. Only through understanding can we avoid future hearing loss. Take a look at Sonic Technology Products if you want to explore sound amplifiers for seniors.

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