Battling fear, grief and depression while undergoing chemotherapy, he self-medicated with drugs, sought professional therapists and went on an ayahuasca (a plant-based psychedelic) retreat. None proved effective in fighting his feeling of hopelessness.

Then Maejor “started getting introduced to different spiritual communities”, he says. “I started hearing about how people used sound.”

After profound experiences during yoga and meditation sessions, he began researching the mechanics of music and the underlying theories connecting the frequencies of specific notes and wellness.

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Referring to the musical note of A, Maejor explains that for the past 80-odd years, “the standard tuning of music has been A equals 440 hertz”. Such a crucial determination, he says, “is just not questioned, not even really deviated from”.

“Hertz” is a measurement of repeating patterns that signifies the cycles per second at which air molecules vibrate as sound travels. A tuning fork that resonates in the key of A, when struck, will cause a wave of 440 hertz to vibrate air particles.

Prolonged listening to these 432-hertz tones, they claim, reduces stress, “detoxifies” cells and organs, eliminates fear and wipes out negativity.

These beliefs are part of a long fascination with “pitch correcting” the Western music scale. Over the past decade, the conversation has eased its way onto social media and wellness platforms.

“Things that I used to talk about a few years ago that seemed very far out or woo-woo are now more normal,” Maejor says.

He documents his journey through his cancer diagnosis – it’s in remission – and turn toward 432-hertz music on his podcast. Maejor Frequency centres around the artist travelling the world in search of information.

Apps such as Calm, Meditopia and Headspace offer daily regimens designed to encourage mindfulness.

On YouTube, hubs release content that has generated billions of views. Spotify and other music platforms offer a lifetime’s worth of pure tones for meditating. TikTok’s “frequency music” hashtag offers countless portals into a range of aural philosophies.

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“432 is one with the world around it. We are all one. Everything is one,” Maejor testifies on his podcast.

The argument for a switch from 440 to 432 hertz rests as much on feeling as it does on science. Most people wouldn’t be able to discern such microtonal shifts up or down eight hertz.

Ruth Rosenberg, a music professor at University of Illinois Chicago, started studying 432-hertz music in the mid-2010s. After researching the alleged negativity of 440 hertz, Rosenberg was struck by “this idea that pop music could be harmful to you”.

“If you do an A and B comparison between a 432 and a 440, most people don’t hear an audible difference. But people will tell you they profoundly do, and what I took from the listeners is that they experience something really different,” says Rosenberg.

One voice Maejor was drawn to was Ana Netanel, who describes herself on her Shakti Sound Bath website as an “international wellness practitioner and instructor specialising in the restorative and healing power of sound frequency and vibration”.

Netanel says: “Healing sounds help to activate the parasympathetic nervous system, which is responsible for rest and digest, and they really help to relax.” Like Maejor, Netanel’s goal “is to bring sound healing to the mainstream”.

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If they succeed, they are likely to face resistance from the medical and science communities.

“So far as I can tell there is very little solid scientific evidence supporting any of these interesting new ideas,” says Dr Robert Bilder, director of the Tennenbaum Centre for the Biology of Creativity at the UCLA Semel Institute for Neuroscience and Human Behaviour.

One of his current students, he says, is getting ready to begin “a randomised controlled trial to see if Tibetan singing bowls have more benefits for psychological well-being relative to a simple relaxation meditation session. But so far there are few rigorous studies of these effects.”

Netanel and her sound-healing students regularly converge on land overlooking the Pacific Ocean to relax to the sound of singing bowls tuned to 432 hertz and gongs that blitz the eardrums with volumes of various frequencies.

On a recent Sunday afternoon, about 50 of us are inside a wide circle of gongs, bowls, shakers and rain sticks to lie down and be bathed.

We recline into savasana, or corpse pose. Sitting before a trio of gongs, Netanel starts gently tapping a padded mallet on the largest of them; her students do the same on theirs. A deep, harmonic drone cascades across the landing and vibrates my eardrums.

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Gradually the gong tones start expanding with higher frequencies as the practitioners activate tuned bowls. A harpist gently strums out vague dots of melody.

At some point, the players return to gongs, activating them with a power that at first feels like angels revving their wings, then God piloting a jet-fuelled chariot.

Fifteen minutes later, a resonant hum is scoring my drive home. It’s reverberating from an experience that had less to do with any specific frequencies, and everything to do with getting lost through meditative, focused listening.

Truth be told, 440 hertz has never let me down – as far as I know.