How Hearing and the Ears Work

All the sounds we hear begin as waves or vibrations. These sound waves come in all kinds of shapes and sizes. If you ring a tiny bell, for instance, the rapid vibrations caused by the metal being struck will create a high-frequency sound wave that produces a high-pitched ring. If you strike a bass drum, the relatively slower vibrations of the drum's surface will send out a low-frequency sound wave that produces a low-pitched boom.

The human brain can hear as many as 7,000 distinct pitches, each created by a sound wave with its own unique frequency. When we hear sounds, it's a result of these sound waves entering our ear canals and beginning an intricate process of transforming into signals that our brains can interpret and understand. To understand how that process works, we first need to get familiar with the basic anatomy of the ear.

The ear is made up of three main parts: the outer ear, middle ear and inner ear. These three parts work together to capture sound waves and transform them into signals our brains can recognize. Each main part of the ear has distinct functions in the overall process of how we hear, which is why it's imperative to take care of your ear health.

Let's follow a sound wave through the ear to get a better understanding of how ears work and what role they play in the hearing process.

Not all sound waves follow the above process. If we heard and processed every sound wave traveling through the air, we could easily be overwhelmed by sensory overload. Instead, humans evolved to perceive sound waves within a limited range of frequency.

The frequency range of human hearing is generally between 20 Hz and 20,000 Hz. Low-frequency sounds below 20 Hz are called infrasound, while high-frequency sounds above 20,000 Hz are considered ultrasound.

Examples of infrasound include noises made by whales, elephants and giraffes to communicate over long distances. And dogs are notorious for their ability to pick up on ultrasound frequencies that are too high for humans to hear—up to 46 kHz! You may be surprised by the various animals that have better hearing than humans.

High frequencies are usually the first to be affected by hearing loss as we get older. Those with high-frequency hearing loss may have trouble hearing sounds in the 2,000 to 8,000 Hz range, making it difficult to understand female or children’s voices or to perceive consonants such as S, F or H.

An audiogram can help determine whether there’s been any loss of hearing perception and be the first step toward counteracting any loss of function in the inner ear.