It’s unsettling to realise that the colours you perceive might be different from those everyone else sees. The same, it turns out, is true of hearing. It’s the uniqueness of each person’s hearing that an ambitious Australian start-up is capitalising on, with an invention dubbed the nuraphone – headphones designed to adapt their sound to the user’s individual hearing profile.

Electronic tones sweep up into inaudibly high frequencies before a kind of pulsing science-fiction minimalism fills my ears as I calibrate the nuraphone I’ve been sent, a visual representation of my hearing profile forming on the screen of my mobile phone, a blob of soft pink and blue.

Nura, NuraphoneNuraphone hearing profile. Photo: supplied

The headphones, launched with a wildly successful Kickstarter campaign in 2016 (it was the largest ever in Australia), are the brainchild of Luke Campbell, who co-founded the company Nura in 2015. “It all started from the simple realisation that everybody hears differently and we’re not talking about hearing loss, we’re talking about the normal variations between two unique individuals,” he tells me.

Campbell’s background is in medicine. “I was training to be an ear, nose and throat surgeon, and on the side of that I was doing a lot of research on hearing and hearing science,” he says. “As part of that research we were doing a lot of what are called objective tests of hearing, which is kind of like what Nura uses, tests of hearing where the user doesn’t have to push a button to say if they can hear it or not.”

There’s quite a wide range within what is dubbed ‘normal’ hearing, Campbell explains. “From a medical or audiological definition, you are said to have normal hearing if your sensitivity at a particular frequency is not worse than 20 decibels,” he says. “Now 20 decibels is massive – if you put your iPhone on full volume and then click down seven times, that’s 20 decibels.”

It’s this variation that’s measured in the nuraphone calibration process, with microphones measuring the ears’ responses – tiny signals from the cochlear called otoacoustic emissions – to the tones played by the headphones. “In a simple sense we use the sensors in the headphones to scan your inner ear, work out what frequencies you hear well, what frequencies you hear not so well, then automatically re-balance all your sound to better match your hearing,” Campbell says. “So if you hear at 2 kHz better than other people than we push 2 kHz down, if you hear at 1 kHz a little bit less well than other people, then we’ll bump that up a little bit for you.”

The end product was based first on data collected by other people, and then later – as more people used the product – by measurements taken from the nuraphone users themselves. “Now we’ve had so many people use our headphones, we’re able to learn from measurements our headphones have been making to improve our sound,” Campbell says, adding the caveat that “any data we use is used in a completely de-identified way.”

When I try it out, the result is striking. The sound is full and detailed, first in the nuraphone demo track and then when I test it on Daniel Harding’s recent recording of Mahler’s Fifth Symphony with the Swedish Radio Orchestra. The Nura app allows you to toggle between your personal profile and a neutral mode, and the sound completely flattens out when I toggle off my profile. “It doesn’t matter what we do with neutral mode, after people switch to personal they tell you neutral’s doctored,” Campbell tells me, admitting that they actually improved the neutral mode in a recent update. The kicker, he says, is comparing your profile with somebody else’s profile.

So I recruit a test subject (not very scientifically) from my household. She’s impressed after setting up her profile, but her smile becomes a grimace when she switches to mine. We swap, and while her music choice (Gretta Ray’s Drive) sounds clear as a bell to me in my profile, I change to hers and it becomes strangely occluded, unpleasantly soupy.

The effect is worse on the Mahler, the upper registers overly loud and tinny, with a hiss in the speakers during the quieter moments that makes the Adagietto almost unlistenable. I switch back to my own profile and the hiss disappears, the sound clear and beautiful again.

“Some people you’ll be like, ‘OK, much of a muchness,’ but then you get people every now and again where you’re like, ‘How are you listening to that?’ And they’ll be saying the same thing to you,” Campbell says.

“When we first developed the idea, we didn’t even know – I mean, it made sense to us – but we didn’t know if it would really make that much difference,” he says. “Or if people would really care when you made these sorts of relatively subtle adjustments.”

But people responded. “Even from the early prototypes that we were making a year or two ago, it was very obvious from the start that we were definitely on to something,” he says. Since the first releases a firmware update has also added noise cancellation to the headphones.

Nura, NuraphoneNuraphone. Photo: supplied

Having demonstrated the headphones around the world, Campbell describes a pair of brothers who almost came to blows over their hearing profiles. “One was 20, one was 21, and they looked like twins,” he says. “One of them tried it and then the other tried it, and then we got them to swap between each other’s profiles. I’m not kidding, they almost started fighting.”

“They started a yelling match,” he says. “Telling each other that they could not possibly like the profile that the other one was listening to.”

Overall, Campbell describes the philosophy behind the headphones as one of getting out of the way, the nuraphone designed to overcome differences in the user’s physiology rather than messing with the sound itself. To that end the Bluetooth headphones come with an array of cables, from USB to analogue. “You’ll probably want analogue cables,” he says when I mention the hard-core classical music audiophiles. “For us it was very important that the headphones sounded good with all types of music, with classical music, with rap, with jazz, with just normal pop music, with electronic music, etc. And so when we were developing it we were testing it with all these types of music and with people from all different backgrounds.”

“There’s enough people in the world who do want to experience music in a richer way,” Campbell says. “People who want the enhancement that you get from sound that’s personally tailored to you.”

Having now spent a bit of time with the nuraphone – and worked through a lot of very different of music – it’s hard to argue with the sound quality. The only drawback for me initially was the sound of my own heartbeat ringing in the silent vacuum of the headphones’ embrace, but that soon faded into the background (and interestingly my test subject didn’t experience this at all).

Campbell is the first to admit that the nuraphone is very experiential. There’s only so much you can glean from reading about it online, and with a sticker price of $499.00 buying one is not a cheap experiment (though they are by no means the most expensive headphones on the market). Nura therefore has been popping up SoundStudios in Sydney and Melbourne (and New York) at which people can try out the headphones – listening to both their own profiles and those of other people – while the company also offers a 30-day satisfaction guarantee.

There are many fine audio options out there, and everyone will have their favourites, but the nuraphone is definitely worth investigating, posing as it does interesting questions about the efficacy of the highest quality audio equipment when listeners’ ears themselves are so variable. It’s a unique, and very convincing, listening experience but it’s also fascinating and a lot of fun to get a sense of how other people hear the world.