Understanding the Human Hearing Range: The Sounds We Can and Can't Hear

Stand outside on a warm Central Queensland evening and the air is busy. Cicadas saw away in the gums, a curlew calls down the street, and far off there is the low roll of a storm that has not arrived yet. All of it reaches your ears at once, and yet it is only part of what is out there. This article is a plain science explainer about the human hearing range.

What "Hearing Range" Actually Means

When people talk about a hearing range, they usually mean frequency, which is how fast a sound wave vibrates. It is measured in hertz (Hz), one hertz being one vibration per second, and 1,000 hertz is written as one kilohertz (kHz). Low frequencies are heard as deep, rumbling pitches, high ones as thin and whistling.

Frequency is a separate idea from loudness, which is measured in decibels. The World Health Organization describes sound in both terms. A sound can be loud and low, like distant thunder, or quiet and high, like the hiss at the top of a cymbal.

The Familiar Numbers: Roughly 20 Hz to 20 kHz

The commonly cited human hearing range is about 20 Hz at the bottom to about 20,000 Hz, or 20 kHz, at the top. That figure appears across audiology and acoustics teaching from bodies including the National Acoustic Laboratories and university physics departments, and it describes a broad textbook span rather than an exact boundary, because it varies from person to person.

Within that wide span, one narrower band does most of the everyday work. Hearing Australia and the National Acoustic Laboratories describe everyday speech sounds as sitting largely between roughly 250 Hz and 8,000 Hz, the region often drawn on the audiogram from a hearing test as the "speech banana". The frequencies carrying a chat across the kitchen bench occupy only a slice of the whole range.

Where Everyday Sounds Sit

A mosquito's whine comes from wings beating a few hundred times a second, which is why it lands in the higher-middle part of the range and feels so piercing at two in the morning. A diesel engine idling sits far lower down, while a child's shriek and the top notes of a violin sit near the thin end.

Cicadas deserve a mention in any Queensland list. The Australian Museum notes that Australian cicadas are among the loudest insects in the world, with the greengrocer cicada often cited as a record holder. Their song is concentrated in a band human ears happen to be sensitive to, which is why a summer chorus can drown out a conversation on the back steps.

Below the Range: Infrasound

Sound does not stop at 20 Hz. It simply stops being something we hear as a pitch. Sound below that point is called infrasound, and it is all around us in thunder, ocean waves, wind and heavy machinery. That energy tends to be felt in the chest and through the floor rather than heard, which is why a big storm out over the Fitzroy can seem to arrive in your body first. Infrasound also travels remarkably well, because low frequencies lose less energy over distance and bend around obstacles more easily. It is why you hear the bass from a distant concert but not the cymbals.

Above the Range: Ultrasound

Above roughly 20 kHz sits ultrasound. It is entirely real, simply outside the window human ears are built to detect. Medical imaging, industrial cleaning and distance sensors all put it to work.

How Animals Compare

This is where the human hearing range gets its clearest perspective, because other animals have windows in very different places.

Comparative hearing charts published by veterinary schools, including Louisiana State University, put dogs at roughly 67 Hz to 45,000 Hz and cats higher again, up to around 64,000 Hz. That is the whole premise of a silent dog whistle. It is not silent at all, it simply sits above our ceiling and inside theirs. Bats go further, with echolocation calls reaching well into the ultrasonic range and researchers measuring some species above 100 kHz. On a summer evening in Rockhampton, the microbats overhead are holding a noisy conversation we cannot attend.

Then there is the opposite extreme. Elephants use very low frequency calls, some of them infrasonic, and the Cornell Lab of Ornithology's Elephant Listening Project has documented these rumbles carrying over long distances. Baleen whales do something comparable underwater, and NOAA Fisheries describes blue whale calls as among the lowest frequency sounds any animal makes. A cattle bellow across a paddock is loud, but nothing like as far reaching.

A Range That Shifts Over a Lifetime

One biological fact rounds out the picture. The upper edge of the range is not fixed for life. Sensitivity to the very highest frequencies is typically greatest in childhood and narrows across the decades, which is the basis of the "mosquito tone" novelty, a roughly 17 kHz sound many teenagers can hear and many adults cannot. It is simply how the biology of hearing is described, much as flexibility and eyesight are described as changing over a lifetime. That gradual shift is the subject of a separate article on how age affects your hearing.

So the next time the cicadas start up, or thunder rolls in from the west, remember you are hearing one slice of a much wider world of vibration, and that the animals sharing the yard are each tuned to a different slice of their own.

If you'd like to chat about your hearing, the friendly team at CQ Audiology in Rockhampton is here to help. Call (07) 4848 6528 or book online.

This article is general information, not personal medical advice. For guidance about your hearing, speak with a qualified professional.

Sources: World Health Organization (frequency and decibels); Hearing Australia and the National Acoustic Laboratories (speech frequencies, audiograms); Australian Museum (cicadas); Louisiana State University School of Veterinary Medicine (animal hearing ranges); Cornell Lab of Ornithology Elephant Listening Project; NOAA Fisheries (blue whale calls).