(CNN) — Seven years ago, American Libby Green was traveling with her mom in Italy and France, capping off their trip with a visit to the southern French Mediterranean resort city of Nice before flying back to the US.
Meanwhile, German-born Marcel Gnauk and a friend were also in Nice, attending the Crossover Festival, a celebration of eclectic music.
Walking on the city's beachfront Promenade des Anglais, Marcel spotted Libby wielding a Hasselblad, a traditional medium-format film camera, and couldn't resist approaching her.
"I love old cameras, Hasselblad, that's amazing," he recalls telling her.
The pair chatted about the camera and travel, and he invited her to go to the music festival that evening. The next day, Libby flew back to the US, but they kept in contact.
Less than a month later Libby traveled to Italy, and she and Marcel, who was working in Switzerland, met up again.
"That's when I think we knew, okay, this is something special, something serious," says Libby.
In 2022, Libby and Marcel recorded sounds in Bangkok's historic railway station.
Libby & Marcel
Marcel then visited Libby in Los Angeles, where she was working in the film industry after studying cinematography, and they traveled together for a few weeks around California.
By that point they knew they wanted to be together and travel the world.
So, Marcel returned to Switzerland, Libby stayed in LA, working for another five months to save money.
They bought a campervan, and in January 2015 Marcel met Libby at Zurich Airport.
"In less than a year we had quit our jobs, and sold everything we owned basically," says Libby. They then spent four months traveling around Europe. A campervan trip in Japan followed, then time in Bali, Taiwan, Cambodia and Malaysia.
In the years since their passion has grown, not just for each other, but for a world of sounds, recorded with their high-end microphones, and shared on their social media.
The couple turned a practical issue of recording sound for a travel video they were making in Cambodia into a full time business that sustains their digital nomadic life. But it took some time before they discovered their calling.
'Everything became alive'
In the early years of their relationship, sharing their travel experiences online became part of their routine.
Libby is skilled using a camera. But they struggled to find a focus.
"There was Libby and Marcel trying to be food bloggers," recalls Libby.
"It was a disaster," adds Marcel. "But it was a good learning experience," notes Libby.
Then, in Cambodian capital Phnom Penh, Libby filmed some pigeons taking flight that she wanted to use in a film. But she couldn't capture the sound of their wing beats.
They looked on the internet, searching sound libraries, but couldn't find anything appropriate. So, Marcel took a $100 audio recorder, and went searching for the missing sound to record.
He didn't find any pigeons -- but he did manage to change the direction of the couple's future.
Marcel turned the recorder on in a small construction zone where women were shoveling gravel, listening through a cheap set of headphones.
He was awed not just by the sounds of construction, but there were monks chanting, and motorcycles passing by behind, honking their horns.
"It was just like the sound was falling into my head from all sides," says Marcel. "Everything became alive, and from that day until now I have never stopped recording."
A passion for sound
In the six years since that first recording, Libby and Marcel have captured audio in more than 25 countries, mostly in Asia, Europe and North America, spending months at a time in each nation.
They have developed a more sophisticated recording setup to encompass stereo, Ambisonic and binaural techniques -- but still compact enough to fit their traveling lifestyle.
This has meant investing in high-end microphones and recorders to fulfill their ongoing passion of sharing authentic soundscapes from each location.
"We are documenting the world through sounds," says Libby. "We are also trying to be a source of inspiration for others to look at sounds in a different way."
It can be an expensive passion. Typically, high fidelity recording equipment stretches into the thousands of dollars for individual microphones and audio recorders. For example, one of their stereo recording kits encompassing German made microphones costs around $8,000.
But for Libby and Marcel it's not just about equipment. Their aim is to really experience a place through sound.
For instance, they took two days to visit Iceland's now well-known black sand beach at Solheimasandur. They made the two-hour hike there and back carrying their equipment, spending up to 10 hours each day recording in the wind and hail.
A favorite memory was recording around the iconic wreckage of a US Navy Douglas aircraft that force landed on the beach in 1973.
"It was just amazing, how it sounds, how the metal is cracking in the wind," says Marcel.
In 2020, the couple took their mobile recording studio to the coast of Iceland.
Libby & Marcel
Two hundred meters from the abandoned aircraft, waves crashed on the black sand beach.
"The terror of the water. This is something you have to experience," adds Marcel. "If you just go there and take a picture and then you leave, you are missing out on so much."
Free To Use Sounds
Libby and Marcel share these experiences through Instagram (@freetousesounds) and their YouTube channel (Free To Use Sounds -- Traveling for Sounds). Through their postings they offer not just their passion and experiences recording sounds, but also details of the equipment and techniques they use. Libby shoots and edits their YouTube videos, and manages their website (www.freetousesounds.com). Marcel does most of the sound recording and editing, as well as the social media postings.
Through their website they offer 500 royalty-free sound libraries. Of these, 145 are free to download.
A passion becomes a business
Marcel says their "a-ha" moment came when he was sitting in front of a computer in 2017.
Libby had added a donation button to their website, and a Hollywood post-production creative had donated a few bucks.
"I'm like, 'Oh! We just made three dollars!'" recalls Marcel of their first donation.
It was then that he realized others shared a passion for sound -- and were willing to pay for it.
"We wanted to be a source that's affordable for all types of people to download the sounds," says Libby.
From this beginning Libby and Marcel have developed a suite of premium sound libraries for purchase as well as free to download sounds.
And they're still excited to travel to new places and record new sounds.
"It does not feel like work because we are just loving what we are doing," says Marcel.
"I know we are still going to be traveling, still recording sounds in five years," adds Libby.
The challenges of a nomadic life
As for the drawbacks of the nomadic lifestyle? Libby and Marcel have no home base and are constantly traveling. They've fought through tough times, almost running out of money.
"When you have a home base you have more of a concrete routine," says Libby. "For us it is always changing, so sometimes that takes more effort, more money."
Marcel in Hong Kong, in 2020.
Libby & Marcel
"And we have so much backlog of sounds," adds Marcel, referring to their unedited recordings. "It is more exciting to record, to be in the present than sitting back with studio headphones."
But the couple prefers to work on their own, without outside assistance.
"We don't have anyone else besides us, it is just the two of us," says Libby. "Maybe it's trust issues, but for us, we know what we can do".
Where to next
Libby and Marcel recently left South Korea to continue their travels in Malaysia. Their next big plan is to travel the Pan American highway from Alaska to Ushuaia, towards the southern tip of South America.
"I think going to Antarctica to record sounds would be a dream. 'Whoosh, a glacier breaks off,'" says a smiling Marcel.
But whether it is a transcontinental road trip, or the frozen wastes of the Earth's southernmost continent, Libby and Marcel's passion for each other and the sounds they record will always be with them.
And, as Marcel says, "It takes us 45 minutes to pack our stuff and be at the next airport."