The year was 1725. Handel ruled the charts with Rodelinda, regina de’ Longobardi, Keaweʻīkekahialiʻiokamoku was about to stop ruling the big island of Hawaii, and in the small northern Italian town of Pesariis, the clockmaking company Fratelli Solari was founded. A mere 223 years later, two Solari descendants—Remigio and Fermo—would start an offshoot company called Solari Udine and change travel forever. (FWIW, looks like their website hasn't been updated since then. -Ed.)

The name of that change was the Solari board, a.k.a. the split-flap display. Admittedly, neither is a name that rings bells for most people, but most people instantly recognize the sound of a Solari board, with its cascade of clack-clack-clacking. Likewise the sensation it triggers: the building anticipation of heading someplace over the horizon.

“I grew up listening to the ‘fwip-fwip-fwip’ of the board at Bangkok’s original international airport, Don Mueang,” says pilot, cinematographer, and Boeing 747 simulator owner/operator Joe Corrigan. (I take exception to that auditory description. -Ed.) “There was the one big departures board, and you’d stand underneath and wait until your flight displayed. The sound it made was mesmerizing.”

That said, let’s take a step back and look at the origin of the Solari board. Believe it or not, these clockwork public information boards started as, well, clocks. (Seems legit, given the family business. -Ed.) Featuring white numbers on four black flaps with 10 numbers each, the Cifra line of clocks debuted not long after World War II, early examples of what would become mid-century modern design.

Wondering—presumably—if the Cifra mechanism could be scaled up, Solari began to experiment. And when 1956 rolled around, the result of those experiments was unveiled. Hot on the heels of the latest iteration of the Cifra clock—the Cifra 5—winning the Compasso d'Oro award for industrial design, the first Solari board made its debut, dangling from the rafters of Liège, Belgium’s railway station, 40 flaps wide.

From there, the sky was the limit—literally—as Solari boards became fixtures in airports worldwide, as well as pretty much any place with departures and arrivals of some kind. (There’s even one in Rocky III’s opening montage, the best of all the Rocky movies. Don't @ me. -Ed.) But as anyone with a mechanical watch will tell you, clockwork mechanisms need regular maintenance. And the further out from production one is, the harder it is.

That Solari boards were transit hub fixtures for so long says as much about how essential they were as it does how long it took digital signage to scale up to that kind of legibility across such a large area. It wasn’t even until late February 2020 that Changi Airport in Singapore retired its last Solari board. As the date approached, people turned out in droves to get one last look at the ol’ flapper—but nobody stopped to admire the digital boards around it.

Progress has never impeded nostalgia, however, and that’s why Solari boards have yet to go quietly into the night. Flying Qantas from Sydney or Melbourne? You’ll find Solari boards in the First Class lounge at both SYD and MEL—and not just for aesthetic reasons. This is how passengers keep track of flight status, the clack-clack-clack alerting them to any changes. (Does that include alerts if any of the hoi polloi get upgraded? -Ed.)

And from where might the world’s safest airline have sourced these uniquely suitable boards? Chances are, someplace like Oat Foundry in Philadelphia—if not Oat Foundry itself. “In 2015, [we] were presented with the task to build a split flap display that used modern technology while maintaining old-school functionality. This task certainly fit under [our] ‘Build Cool Stuff’ umbrella, so we built it—and kept on building them.” So far, Oat Foundry’s built boards for cruise lines, hotels, breweries, and even the Chicago Cubs.

Technology moved on from the Solari board—and that’s fine. Solari Udine itself doesn’t even make boards anymore. But they do still make Cifra clocks. And Oat Foundry is out there making split flap displays. What does that say about our connection to those clack-clack-clacks? Looking to the January 2016 issue of The Annual Review of Psychology, “Auditory information… plays an important role in guiding our other senses, such as when we hear a sound and turn our head to look. Sound provides a kind of connective tissue, ensuring the continuity of our experience over time and choreographing the focus of our senses.”

The era of the Solari board as transit hub feature has gone. That can’t be debated any more than it can be undone. But there’s a collective memory of what it stands for—just look at the centerpiece of the TWA Hotel—even among people without any firsthand experience. The Solari board may be obsolete technology, but it’s as tangible—and valuable—an experience as it ever was.

Solari Boards: The Disappearing Sound of Airports [via The BBC]