Our hearing

And you probably wouldn’t miss out on music, the laughter of children, or the caring words whispered by a loved person either. Or what about nature’s comforting sounds: the evening song of a blackbird, the wind in the autumn leaves, the waves on the beach or the cracking sounds of a cosy bonfire.

How our hearing works

We have two ears and a brain to hear with. And for good reason.

Natural hearing
A healthy hearing system can recognise both low sounds (a double-bass or traffic) and high (a violin or the twittering of birds). In technical terms, that means frequencies between around 20 and 20,000 Hertz. What’s more, it can process very quiet sounds (the buzzing of a mosquito) and extremely loud sounds (a jet engine starting). This equates to volumes between 0 and more than 120 decibels.

Understanding speech
Our brain is particularly adept at understanding language, which it can cope with in all its various facets and in every situation. Whether we are sitting in a café, on the phone or in a lecture, our brain filters out a flood of irrelevant sounds to concentrate on those that we need to hear. It is thanks to this facility that we are able to focus on a single instrument in a symphony orchestra, or participate in intimate conversations in a noisy environment.

Spatial hearing
Our brain hears sounds 360 degrees around the head – at every angle around our head. Our brain can differentiate between front and back, up and down. This lets us tell where a sound is coming from, how big a room is or whether there is an obstruction in the area.

The brain works hard

Many people find it challenging to follow conversations in some places, like in a noisy restaurant. This is because speech is made up of a large number of different sounds, put together in very rapid flow. Our brain constantly prioritises and organises all these sounds for us.

When it comes to hearing, it may come as a surprise to learn that the brain works harder than the ears. This is why in noisy environments, such as in a crowded restaurant, it can be very frustrating just trying to follow conversation. Even people with no hearing loss can find this challenging. Ordinarily your brain will be able to sort through all information you apply your attention to through a cognitive process: Put simply, the brain organises the sound environment, selects the desired source and follows it. For people with hearing loss, however, the brain has to work much harder to make sense of sound because the input it receives from the ears is softer, less detailed, and/or unclear

Some sounds are heard better than others
The high-pitched consonant sounds like f, s and t are easily drowned out by louder, low pitched vowel sounds like a, o and u. This results in a person with hearing loss complaining that they can hear that others are talking, but not what they are saying.