For 45 years, The Manhattan Transfer has entertained audiences with its blend of energy, joy, class and cool. It’s brought the group 10 Grammy Awards, fans around the world, and memories to last a lifetime.

What’s kept them together without, as Variety magazine put it, having “aired a shred of dirty laundry”?

“It was a great idea when Tim Hauser came up with it, and it still is a great idea,” said Janis Siegel, whose scat singing is one of the hallmarks of the Vocal Group Hall of Fame act.

Back in 1972, Hauser was an aspiring singer who had performed with several groups. His day job as a taxi driver brought him in contact with Lauren Masse and then Siegel, both of whom had been singing in other pop groups. Broadway performer Alan Paul, the friend of a friend, was brought on soon afterward.

Masse left in 1978 after a car accident and was replaced by Cheryl Bentyne, but from then on The Manhattan Transfer stayed intact — and the hits piled up — until Hauser’s death three years ago.

The group won Grammy awards in both pop and jazz in 1981 for “The Boy from New York City.” Siegel’s brassy, sassy soprano leading the tune is so cheerful that you can almost hear the smile on her face. That was followed with repeat Grammys over each of the next two years for Best Jazz Vocal Performance, Duo or Group, then three more Grammys (out of 12 nominations) from their 1985 album “Vocalese.”

Siegel remembers being immediately drawn to what Hauser was aiming for: mixing genres like soul, R&B, jazz, pop and rock into a fun, easy-on-the-ears sound. It’s a formula that worked for doo-wop groups of the ’50s and The Beatles of the ’60s, and post-Manhattan Transfer, even the retro “Chant” singers who turned 11th-century Gregorian prayers into a ’90s hit.

“That’s what struck me, actually singing the four-part harmony,” Siegel said in a phone call from New York City, where she grew up and continues to live. “I’m a harmony freak.”

“It always came naturally to me, hearing harmonies,” she said. “I had some rudimentary knowledge of piano and how to write down music. I just started by doing it. … I used to do head arrangements. You just came up with it, and remember it.”

In the wake of Hauser’s 2014 death, Trist Curless joined the group. The founder of pop-jazz vocal group M-Pact boasts a full, deep bass singing voice.

“He’s not only a masterful musician, he’s really a true bass singer,” Siegel said. “And he’s a great collaborator, very supportive, a hard worker, and a lot of fun on the road.”

Siegel herself doesn’t just rely on her experience to make the music work. She started formal vocal training in 1980 and has kept up with it ever since, and it’s paid off. At age 64, she still sings most of the songs in the same key as in the group’s early days.

“I realized the value of it, certainly for longevity,” she said.

She also remains actively involved in seeking out new music and new artists. Just the morning of her interview, she’d been listening to Tune-Yards, a New England artist that combines looped beats with electronic music, ukulele, strings and vocals, along with music from jazz guitarist Steve Khan and singer Al Jarreau. She recently sat in with multitalented singer-songwriter Raul Midon, who wowed Honolulu audiences three years ago.

“I listen to artists who are unique,” she said. “They’re saying something, or there’s something distinct about them.”

Although The Manhattan Transfer has long been known as a pleasing, audience-friendly act — their elegant, synchronized presentation recalls the smooth stylings of groups like the Four Tops and The Temptations — Siegel prefers to work in the studio.

“For me, I love the studio. I look at it as an instrument,” she said. “What I like about it is that the focus is completely on the construction of music. There’s no audience to please, there’s no outside distraction. It’s just the creation. … Performing is a different animal. It’s a completely different way of singing, of projecting yourself.”

That said, she still loves to perform. Of the many great concerts they’ve given, among her favorites are “anything we did in Italy.”

“We played on the beach in Positano, we played in the middle of the town square in Assisi, we played in a shopping center outside of Milan,” she said. “The country, the food, the wine, the vibe. … They love music, and they appreciate art.”

Celebrating its 45th anniversary, the group is doing two gigs at Blue Note Hawaii separated by a few days midweek.

Expect to hear the favorites, plus some new stuff as well, because the group is putting the finishing touches on a new record — “the first one since Tim died,” Siegel said. “It’s tentatively called ‘The Junction.’

“There’s quite a few original things, in some capacity. We did a version of (Herbie Hancock’s) ‘Cantaloupe Island,’ which should be quite interesting. … There’s some jazz things, some jazz-pop things.”

The album will include “one little political statement,” Siegel said. Despite their squeaky-clean image, the group in fact does have a history of the risque, having some songs banned from their television show in the 1970s.

“Why don’t we just say we covered Ricki Lee Jones’ ‘Ugly Man,’” Siegel said with a laugh. “You can make of that whatever you wish.”