The two sides of Charlie Puth: baby-faced tween idol and hard-core music nerd

The shrieking of little girls filled the air at Staples Center when Charlie Puth took the stage last month during KIIS-FM’s annual Jingle Ball concert.

A baby-faced pop singer best known for “See You Again,” his chart-topping duet with rapper Wiz Khalifa, Puth wasted no opportunity to milk the crowd’s adoration. There was grinning. There was crooning. There was the furrowing of his brow with oh-so-cute sincerity.

Yet on a recent morning at his home in the Hollywood Hills, Puth, 24, came on less like a tween idol than an experienced studio pro as he described mixing a rhythm track for another of his songs.

“The trick is that you want to be able to hear the kick drum pop,” he said before getting deep into technical language that left a visitor looking adrift. “Oh, just think of ‘Pretzel Logic’ by Steely Dan,” he finally offered. “To me, that’s one of the most brilliantly mixed records of all time.”

This is the blend of puppy-dog appeal and musicianly know-how that’s endeared Puth to two camps not often in accord: young pop fans, who’ve driven “See You Again” and the doo wop-flavored “Marvin Gaye” to multi-platinum sales, and more conservative listeners like Recording Academy members, who nominated Puth for three Grammy Awards, including the prestigious song of the year prize.

Compare that to a single nod for Justin Bieber (for his cameo on a dance cut) and a shutout of the mega-popular One Direction.

Now, with a debut album, “Nine Track Mind,” set for release Jan. 29 — just weeks before the Grammys are handed out Feb. 15 — Puth is looking to that unusually broad base to help him launch a long-term career à la Bruno Mars or Justin Timberlake, to name two established stars on whom kids and their parents have agreed.

“Nine Track Mind” should please both groups. It has catchy, cheerful tunes like “One Call Away” with big, simple melodies that show off his sweet tenor. But the album, much of which Puth produced himself, is also streaked with inventive arrangements and vivid turns of phrase, as in the propulsive “My Gospel,” about the lengths he’d go to for a lover, and “We Don’t Talk Anymore,” a convincingly sensual duet with Selena Gomez.

A New Jersey native who studied jazz piano and music production at the Manhattan School of Music and the Berklee College of Music, Puth first made a name for himself writing and producing for other artists such as Trey Songz and Jason Derulo. He even wrote “See You Again” — which appeared in “Furious 7" as a tribute to the film series’ late star, Paul Walker — thinking someone else would sing it.

Yet he knew he didn’t want to stay hidden in the studio. KIIS-FM program director John Ivey recalled being introduced to Puth by the singer’s manager at a quiet Italian restaurant in Westwood.

“Charlie sits right down next to me and starts belting out the hook to ‘One Call Away,’” Ivey said with a laugh. “He’s got a big personality, and he’s willing to share it.”

Things have moved quickly for Puth since “Marvin Gaye,” his debut solo single, came out a year ago. (That title, by the way, turns the soul legend’s name into a verb, as in: “Let’s Marvin Gaye and get it on.”) At his house, which he’d moved into recently enough that cardboard boxes still sat in the garage, he was entirely comfortable amid a blur of handlers as he prepared for an appearance on “The Ellen DeGeneres Show.”

But he hasn’t lost a closely observant quality that allows him to view songwriting with mathematical precision. He talks about the importance of where long notes are placed in a melody, and how a song can be damaged by getting the tempo wrong by just a few beats per minute. He also knows that lacing youthful tunes with hints of vintage styles can widen his music’s audience.

If that seems calculating, it should. This is pop music; calculation is how it’s done.

And it’s not as though Puth isn’t open to grabbing inspiration wherever it strikes. Recounting his process for the song with Gomez, he pulled out his iPhone and played a recording of the moment when the melody came to him one day as he drove past the Santa Monica Pier.

Oh, and Gomez’s vocal for that track? Laid down not in a fancy Hollywood studio but in Puth’s bedroom closet amid a bunch of hanging shirts.

“That sounds creepy, but the acoustics were great,” he said with a shrug.

Puth knows much of this won’t necessarily be of any interest to the people he’s hoping will power “Nine Track Mind” up the charts.

Mike Caren, who oversees A&R at Puth’s label, Atlantic Records, called the singer “part of that 1% of musicians who hear things differently” and said Puth “isn’t motivated by the same things everyone else is motivated by.”

Still, Puth thinks the care he put into the album will help bring together the two sides of him floating around out there: the handsome Snapchat-era pop star and the hard-core music nerd with a head full of facts about John Coltrane and Neil Sedaka.

“Look, I like people recognizing me on the street and asking to take pictures,” he said. “But it’s honestly not about my ego. It fuels my creativity. Ten girls just came up to me? Wow. Now I want to make another song they can blast in their convertible.”

mikael.wood@latimes.com