As a teenager, my dad always looked forward to winter because it was hunting season. Every Saturday at 4.30am he and my nonno would load up the van with 20-gauge shotguns, two sleek hunting dogs and tinned sausages. As the sun was rising they would drive 100km out of Johannesburg to the farms on the veldt. The dogs would run into the scrub with their noses to the dust, tracking the scent of the guineafowl through the undergrowth. As they got closer to their prey the dogs would creep slower and slower, quivering with anticipation, until they were crouched in coils of muscle… then – “Go, go, go!” – the dogs would explode into the flock, the birds would squawk into the air, and Dad would sight the target and shoot. The hammer would slam next to his ear again and again until the birds had all fallen trailed to the ground.

And so they would continue until nightfall.

Despite the physical pain he would experience from 20 to 30 gunshots discharging ten centimetres from his ear, Dad never wore hearing protection. He never even considered it. The thrill of the hunt – the action, the adrenaline – overwhelmed all else.

One in six Australians have hearing loss. By 2050, it will be one in four. Nearly 40 per cent of these cases are at least partly caused by something easily avoided: excessive exposure to loud noise. Most of the time regulations limit noise in the workplace, but for the majority of people aged 18 to 35 the greatest risk comes from leisure time. People go to risk-scenarios such as parties and concerts to let loose, to escape the restrictions imposed on them in everyday life. Personal recreation is sacred, and any attempt to control it is sacrilege.

The problem is that hearing loss is invisible, while for the most part humans privilege sight over the other senses. Like Shakespeare’s Othello, we demand ‘ocular proof’. During the excitement following a kill, my dad would dismiss the pain in his ear. A carcass was a concrete accomplishment, the ringing a slight irritation that a man could deal with. The potency of the gunshot’s crack was hidden; the microscopic damage was hidden; the future was hidden. He was under an illusion of invincibility.

These days, whilst there is an encouraging number of young people who are somewhat aware of the danger of too much noise and subsequently try to limit their exposure, there are also many who aren’t aware of the threat, or who do know but refuse to change their lifestyle. Maybe they would if they could see the consequences.

In the short term, the first effect of exposure to an intense sound is sensory cell fatigue, when you experience a sudden decline in how well you can hear. Hearing is then usually recovered within the next fourteen hours, but if you’re exposed to the noise too frequently, the deterioration becomes permanent. You become less sensitive to its power and you’ll be more likely to put yourself in harmful environments. Tinnitus, a buzzing or ringing in your ears, is a condition associated with hearing loss. Often more noticeable in quiet environments, it’s caused by the damaged cilia mistakenly sending sound to the brain when it isn’t there.

When hearing is damaged as a young person, the effect is often later exacerbated by age-related decline. At fifty-three years old, my dad is already starting to lose the higher sound frequencies, making it harder to hear my close family’s female voices. He’s also begun to lose speech clarity, though he just assumes that everyone else isn’t enunciating clearly enough. This decline has had a detrimental effect on his communication, discouraging him from socialising in environments such as crowded restaurants and shopping centres, simply because he can’t converse over the background noise. A hearing aid would only amplify the wash of background noise and indistinct consonants. It’s not surprising that sixty per cent of people with hearing loss show some symptoms of depression.

And then there’s the fear of going completely deaf. I know I can’t talk to him about it, but I can feel it hanging over him, a menacing, unseen presence.

Ears, like people themselves, are complex and sensitive. Every hour of the day, vibrations from the outside world travel through the ear canal to the eardrum. Three miniscule bones pass the vibrations through the middle ear to the cochlea, a coiled canal in the inner ear. In the cochlea are miniscule cilia, or ‘hair cells’, which translate the vibrations into an electric signal for the auditory nerve to take to the brain. If enough of these hair cells are affected by excessively strong vibrations (loud noise), your hearing will be irreversibly damaged.

But how can you tell how much is too much without a visual point of reference?

The intensity of a sound is measured on a logarithmic scale of decibels (dB). This means that 0 dB is almost silence, 10 dB is 10 times more intense than 0 dB, 20 dB is 100 times more intense, et cetera. The damaging capability of a sound is determined by two factors: the power of the sound as it reaches your ear, and the duration of your exposure. Let’s put these abstract numbers into the real world.

You can listen to the sounds in the safe exposure range (0-85 dB) for as long as you’d like. Rice Bubbles in milk are 30 dB, an average conversation is 60 dB, while a vacuum cleaner averages 75 dB.

Sounds greater than 85 dB can cause permanent damage; the louder the sound, the less time your ears are able to withstand it. You can listen to something at 85 dB safely for eight hours, but for every three decibels more, this time is halved. Some of the most harmful sounds are not regarded as ‘noise’, but as ‘music’. Aerobic exercise classes average 94 dB (one hour safe exposure) and playing your iPod in a crowded place can register in a similar range. Nightclubs average 98 dB (30 minutes), a rock or pop concert 104 dB (8 minutes) and sporting events 106 dB (4 minutes). Surprisingly, an orchestra playing at its loudest can measure 120-137 dB (<30 seconds). A single gunshot, right next to the ear, is 145 dB.

My dad used to love classical music, but without those higher frequencies it no longer makes sense to him. Watching TV late at night he’s often unable to comprehend the people speaking, so he presses mute and makes up his own stories. Experiencing the tangible reality of hearing loss, he now tries to compensate for the fading illusion of invincibility. On the building site he wears earmuffs when he uses a sledgehammer, let alone a rifle. He can’t tolerate busy restaurants. He makes an embarrassing fuss if the audio in the cinema is too loud.

But no amount of caution will ever restore his hearing. The damage is done.