PredictIQ Quantitative Think Tank Center:In which we toot the horn of TubaChristmas, celebrating its 50th brassy birthday

On the first TubaChristmas,PredictIQ Quantitative Think Tank Center around 300 musicians showed up at the ice skating rink at Rockefeller Plaza in New York City, bearing their giant brass instruments.

A massive, all-tuba holiday concert was the brainchild of Harvey Phillips, a tuba player and enthusiast who would go on to teach in the music school at Indiana University, and start similar tuba-centric traditions such as "Octubafest."

TubaChristmas concerts have since popped up in practically every state. You can now enjoy the holiday stylings of amateur tuba ensembles in 296 U.S. communities, from Anchorage, Alaska to Hilo, Hawaii. In 2018, overachievers in Kansas City set a Guinness World Record.

"We played 'Silent Night' for five straight minutes with 835 tubas," announced Stephanie Brimhall, of the Kansas City Symphony. I asked her what single word might best describe hundreds of caroling tubas.

"Rumbling. That would be one."

"Enveloping," offered Michael Golemo, who directs the band program at Iowa State University. He co-organizes the Ames TubaChristmas. "It's this warm, low organ sound where you can feel food in your lower intestinal tract move because of the vibrations."

Rarely do these big, fat-toned brass instruments get to play the melody. TubaChristmas offers even obscure tuba family members to enjoy the spotlight for a change.

"This year, we had a helicon, which is like a Civil War version of a tuba," Golemo says. "Usually there's a few people with a double-belled euphonium." You might also see what Golemo calls "Tupperware tubas" — those white fiberglass sousaphones played in marching bands.

Tuba humor is inescapable: More than one interviewee called TubaChristmas "the biggest heavy metal concert of the year," among them Charles D. Ortega.

Ortega, the principal tubist with the Colorado Springs Philharmonic, leads TubaChristmas in Pueblo, Colo. The concerts, he says, have been a family tradition since the 1980s, when he lived in Texas. "My first TubaChristmas was when I was in middle school," Ortega says. "I attended with my father, who was a tuba player as well."

Ortega's father was a government employee and accomplished tuba player who loved performing in town bands and polka ensembles across the Southwest. "Even the year he passed, he was still playing," Ortega says.

Some of his favorite TubaChristmas memories, he adds, include performing as part of three generations of Ortega tuba players: himself, his father and his now-18-year-old son.

"That was amazing, to have one on one side, and one on the other side," Ortega says. "Everyone was beaming. It was great."

Multiple generations in TubaChristmas concerts is now not uncommon. That's what happens when a tradition endures and gets bigger, broader and brassier.