They'd never really had a solid tuba player.

The legendary New Orleans music family, of course, had its trumpeters and trombonists, saxes and drummers. But the tuba -- namely the circular kind called a sousaphone -- is big. And it requires a lot of air. And it scares little kids. And it's not exactly cool.

Still, Revell Andrews, even as a shy young teenager, picked up on the need for the instrument's stable foundation in the brass band arrangements his kin play virtually every day in their city's streets and clubs and across the world.

"For Revell, it was more like, 'If this is a need in the family, I've heard it a few times, let me pick up the tuba,'" recalled his loving cousin, drummer Derrick Tabb.

"And it just so happened to be the instrument that everyone needed."

There's another thing about the tuba, though, Tabb said: "You immediately know the difference if you have one there and you don't."

And now, stunningly, they don't.

Not since Revell, 18, was fatally shot while riding in an SUV one Monday afternoon in June, just weeks after his graduation from McDonogh 35 Senior High School.

He'd been with a few close friends -- among a tight crew that shared a group text and checked on each other via phone location -- collecting everyone from their summer jobs, said Katy Reckdahl, the mother of another boy in the group who hosted Revell in her home when his trombonist dad was on tour.

Read other profiles of children who have died from gunfire

Three of the kids, in Reckdahl's Jeep, had stopped at a gas station downriver of the French Quarter, she said. They pulled out around 2:45 p.m., according to a police report, and a 14-year-old allegedly pulled out in a vehicle behind them, a New Orleans homicide detective testified last month about the arrestee in the case, citing witness statements and surveillance footage, CNN affiliate WDSU reported. CNN has reached out to the Orleans Parish District Attorney's Office.

The underage driver then allegedly rolled down their car window and fired, the detective said. Revell got shot in the face and soon died at a hospital, police and his family said -- yet another American teen killed in a nation where firearms remain a top cause of death for youth, federal data shows.

'That's my son's shoes'

Not quite a year old when Hurricane Katrina swamped most of New Orleans, Revell moved with his parents and siblings to Mississippi, said his father, Revert "Peanut" Andrews. When Andrews headed back to the Louisiana music scene, Revell would visit his native 6th Ward and go with his dad to gigs and second line street parades, the musician said, noting, "Everybody called him my twin."

By the time he moved back for high school, Revell's dad had talked with his son of the violence lurking in their corners: "He might go out to the store," the father said, "but he never would hang out there -- because he knew." Revell -- on sousaphone, the bell like a halo above his head -- even helped lay the track for a YouTube video in which another cousin, the renowned trombone player and singer Glen David Andrews, presses for education over violence, intoning:

In New Orleans, stop the killing ...

7th Ward, 6th Ward, 8th Ward

Stop the killing.

"Our little group was not naïve about the city and its sinister level of gun violence," Reckdahl, a local journalist, wrote in a tribute to Revell in the city's daily paper. "It was by design that they stayed home and out of the way. They wanted more in life. But at the most basic level, they wanted to live."

Andrews didn't mind his son's hours of video-gaming, knowing it kept Revell, his girlfriend and their pals safely indoors. He also knew his boy excelled in school -- might even be headed for a college and its marching band. And he couldn't say enough about the instrument Revell was working to learn.

"We never had a sousaphone player," Andrews said. As for a favorite song, Revell "was trying to learn them all."

"I know the sky was the limit for him," he said later.

Andrews and others also knew Revell -- the second-youngest of four brothers -- wasn't a follower, they said.

"That was one of the first things that impressed me about Revell," said Tabb, who runs the Roots of Music program that serves hundreds of at-risk kids every year. "Most young musicians these days ... plug in and immediately start playing; he went to other people's gigs ... and would be waiting" to be invited.

Indeed, Revell was mature, humble, quiet -- "an old man in a young man's body," Reckdahl wrote.

"I never even seen Revell, never saw him mad, never saw him get loud, fight nobody. I can't recall one time," Andrews said, baffled by how he met with such a violent end. But either way, "What, you're gonna keep 'em inside forever?"

In the weeks after his death, Revell's father collected from the mail acceptance letters from colleges that didn't know their offers would no longer be of use, he said. In Revell's room, Andrews found a pair of his son's sneakers -- Jordan 1s -- and slipped in a toe.

"It fits perfect," he said of the 10 1/2s. "I didn't even know his foot had got to that size."

Now, he's keeping them. And wearing them. And telling anyone who asks: "That's my son's shoes."

Andrews will keep the letters, too, he said, along with so many photos and videos of Revell shared by his cousins and his friends of the happy moments of a young life Tabb described not so much as "lost" but "a take."

In them, Revell smiles shyly. And slings his arms around his crew. And dances in the street. And blasts out the foundation on a set of eternal music.