How do we hear? Can you remember those distant sepia tone science classes? Were you even taught about how we hear? Hearing often takes second fiddle to seeing and vision in the hierarchy of the senses- we almost all know that we can see objects via a reception of light waves reflected and refracted off objects. Most of us understand the concept of sound waves, but there is more to hearing and the health of our ears than just this.

 

We at Just Online stock a number of hearing safety products and think that it’s important our customers understand the science of how we hear. Keep reading to have your frequently asked questions about hearing answered.  

 

  1. What sound frequencies can we hear at? We as humans can hear the range of 20 to 20,000 Hz. Specific types of people create a range of hearing along this spectrum. Young people can hear higher frequencies up to 18,000 Hz while older men, at 55 years and up often can’t hear above 5,000 Hz. Here is an interesting link, showing, you, how age and frequency operate, see if you can hear the 17400 Hz frequency for yourself! https://www.yahoo.com/beauty/try-it-can-you-hear-these-sounds-only-young-112627654778.html. Only the young should be able to hear the last frequency on this site. Human hearing is best and most sensitive at 3,500-4,000 Hz.
  2. Why and how do we hear? When sound waves hit our ears. Information is transferred via bone and air conduction. Air conduction starts first in the ear canal, where sound waves are channelled via increased in pressure caused by a narrowing and expanding of the gaps in the ear. Soundwaves then hit the eardrum, the bridge between the outer and inner ear- which translates the information into bone conduction. The soundwave is then conducted through three tiny separate bones called the malleus, the incus and the stapes. (The hammer, anvil and stirrup, in Latin). These bones connect to the nervous system which channels the information provided by the soundwave straight to the auditory cortex, and often to the amygdala too if the noise provokes an emotional reaction. The malleus, incus and stapes also help us hear our own voice, up to 50% of the vibrations caused by our own voice are channelled within the body through these bones- hence, why, when we hear ourselves recorded we sound different. Because we only hear 50% of ourselves.
  3. How, and why, do we hear music: harmonies, timbres, tones and pitches? Our ears can pick up very, very complex and various sound. One kind of sound that operates in a complex way is music, that combines different frequencies, measured in Hz and volumes, measured in dB. Harmony is an interesting function of music and can be explained via the science behind frequency. (more writing here)
  4. Why do we react emotionally to certain sounds? The above mentioned Amygdala area of the brain is responsible for emotional reactions to noise. The Amygdala centre controls things such as memory, emotion, behaviour, motivation and smell. We seem to be genetically programmed to respond to certain sounds, often ones that pose danger to us- the Amygdala takes over our reactions when particularly unpleasant sounds are encountered. Sounds such as scraping and screaming most often cause us to have negative reactions in the Amygdala.  

 

We hope you have enjoyed this brief FAQ on the science of hearing, and we hope this information will help you make informed decisions about our various sound-related products, which can be found at https://www.justonline.co.uk/product-category/personal-safety/earplugs-hearing-protection/.