Sound vs. noise

Harleen Saini
20 December 2018

Imagine  you are studying in your room. Meanwhile, your neighbor’s dog keeps barking. This makes it difficult to concentrate on your notes. After awhile, it starts getting on your nerves. You may think of the barking sound as noise, as it is annoying and not something you want to hear while you try to study for your big test!

Sound vs Noise: Are they the same?

At a scientific level, sound and noise are technically the same. However, sound is something that we hear in general, while noise is something that we can hear, but not necessarilywant to hear.

How do we measure sound?

Sound is measured in decibels (dB), named after the one-and-only Alexander Graham Bell.

One way sound is measured is with a sound level meter. This device has a microphone connected to an electronic circuit and display. It picks up differences in air pressure that are related to sound. These pressures are then translated to electrical signals and displayed as the sound level, measured in dB. This method is usually best for taking a measurement at one point in time. In other words, it’s best for measuring an environment that has a constant level of sound and can be used to see what level of sound someone is exposed to in that area over a day.

Another method is by using a noise dosimeter. This also has a microphone and recorder attached to it, but is used to record sound level throughout the day and then averages the total noise someone is exposed to. This is usually attached near someone’s ear so it can accurately record the level perceived by the person throughout the day. This is best for measuring environments where sound levels constant change and is also measured in dB.

What sound levels are safe and what is dangerous?

In general, sound levels that are below 85 dB are considered to be safe. However, sound levels that are 85 dB or more are considered dangerous. In fact, the louder the sound, the more quickly it can cause permanent damage to your ears. For example, listening to a song at 85 dB for 8 hours will cause permanent damage. But listening to a song at 100 dB can cause permanent damage within 15 minutes!

In case you are curious, here is a list of sound levels and how quickly these can cause harm.   

The levels we discussed above are more cutoff marks, but not exactly levels that what we may hear every day. The World Health Organization (WHO) suggests that the optimal sound level in a classroom, for example, should be at or below 35 dB, and is considered comfortable. However, most people find sounds in the range of 60-65 dB uncomfortable. These ranges are probably closer to our everyday sound level exposure.

Negative Effects of Noise

Noise doesn’t necessarily have to be loud to have an effect on someone’s health. For example, a squeaky door which keeps opening and closing is not loud per say, but can be extremely annoying. Some negative effects of such noise may include:

  • You feel more stressed than usual
  • You might notice your heart beating faster than usual
  • You notice you are more sweaty
  • You are unable to sleep well
  • You notice you get angry or annoyed by the smallest things
  • You feel anxious and uneasy

In some extreme cases, people who are constantly exposed to noises that cause stress can end up with cardiovascular disorders, such as heart attacks or heart disease.

Often, people feel their quality of life can be affected by noise as well. For example, some people have a harder time enjoying their backyard because of nearby traffic or overhead aircraft sounds. There was a Canadian study that showed some individuals were unable to sleep and had headaches due to nearby wind turbine noise.

Did you know?  The stress response of the body (including increased heart rate and blood pressure, feeling sweaty, anxiety and lack of digestion) is often called the “fight-or-flight” response and is controlled by the sympathetic nervous system. The opposite effects occur when the parasympathetic nervous system kicks in (including decreased heart rate and blood pressure and being able to digest).

Positive Effects of Noise

Okay, so we have been focused on all the negatives when it comes to noise. But, there are some positives as well! A study has shown that music can help increase work efficiency, especially when doing routine tasks or less difficult tasks. In fact, it can even promote creative thinking! However, music has also been shown to impair ability when working on more complex tasks, such as learning something new.

In other words, music tends to be more helpful when doing daily chores, but may not be the best idea when you are trying to solve complex physics problems for homework. The reason for this is when you are overwhelmed or stressed, extra noise tends to be less helpful as it can worsen your stress levels. But, it can still be helpful in giving you extra focus when you are just reviewing old information.

Let’s do a little recap...

  • Sound  is measured mainly in decibels. You can measure sound at a specific point in time with a sound level meter or get an average of sound levels over a period of time with a noise dosimeter.
  • Sounds that are 85dB or greater can be dangerous and cause long-term damage to your hearing. Ideally, it is best to listen to sounds less than 85dB.
  • Sound can have negative and positive effects depending on the situation and type. Unwanted sounds (AKA “noise”) which annoy you can lead to a stress response, and make you anxious and irritable. When you’re doing complex tasks (like learning new information), noise can make it difficult for you to focus. However, music can be helpful and make you more creative when doing less difficult tasks. It may also help you focus on certain routine tasks as well.

Sound is not as simple as you may have thought! As you can see, sound and noise can affect you in different ways. Who knew listening could be so complex?

Learn More

How Our Ears Work (2013)
Kids Health

Classroom Acoustics (Accessed 2018)
Speech Language and Audiology Canada

How Loud is too Loud? (Accessed 2018)
Dangerous Decibels

Misophonia: When Noises Can Ruin Your Life (2016)
Let’s Talk Science

Harleen Saini

Hello everyone! I am a premedical student from the United States who is hoping to become a physician one day. My love for science began with watching shows such as Bill Nye the Science Guy and The Magic School Bus series. These helped make science fun and exciting, and eventually led me to pursue an undergraduate degree in Biological Sciences which I completed in 2016. I enjoy being able to share my passion for STEM topics, especially health science and biology, and hope to help others fall in love with the sciences as well. Outside of this, I am also a musician, enjoy dancing and love to learn foreign languages!