A decade ago, while freshman at the University of Southern California in Los Angeles, Georgia Greene and Lauren Jones began writing a tune together for a songwriting class they were taking. Greene and Jones thought what they had could use a boost so they asked Quinn D’Andrea to add a third harmony part to the song.

“The three of us were singing in Lauren’s dorm room and that was the first time our voices came together and it was magical,” D’Andrea told the Boston Herald. “It was pretty instantaneous.”

Trousdale was born at that moment. Fast forward ten years, the trio’s voices are still making magic, on new album “Growing Pains” and on tour — Trousdale’s May 13 show at the Sinclair is sold out but tickets remain for the club’s May 14 date.

There’s a healthy dose of twang on “Growing Pains.” There’s a bit of soul, some Americana, and plenty of pop. But it’s hard to zero in on an exact genre because the women’s vocal blend is so captivating. Those harmonies steal the focus.

“Our harmonies are a great way for us to differentiate ourselves from other bands,” Greene said. “Even if our genres change a lot, our harmonies stay the same so you can always tell when it’s a Trousdale song.”

The voices carry from 2023 album “Out of My Mind,” which has a clean, poppy sound, to the new record and its earthy vibe. Looking for a more organic sound for “Growing Pains,” the trio took producer John Mark Nelson’s advice of tracking much of the record live.

“The program we met at in college was very live performance based so we’re all pretty comfortable in a setting working with musicians in the room and arranging from there,” Jones said. “In a lot of ways, it felt like coming home to our roots.”

In both modern pop and country, this is rarely done. More often everything is tracked separately, sometimes singers and musicians aren’t even in the studio on the same day (if the sessions even use musicians).

For “Growing Pains,” the three singers and songwriters worked with Nelson and their guitarist, bassist, and drummer in a practice space for a few days sketching out the songs. With such sophisticated harmonies, the women needed to record separately from their band. But you can hear that they worked up the tracks together in the final product.

The organic vibe is a nice match for the themes on “Growing Pains” — love, loss, defiance, renewal. It also makes the songs ideal for live sets. And there will be a lot of live sets to come. Just over a week into their tour, the trio has the next five months booked including a trip to Europe and dates supporting hometown favorites Lake Street Dive.

“There’s so much we get from the fans, being around people that love the music, it fills up my glass,” Greene said. “And having (five months] booked means we’re doing something right and not just shouting into a void.”

For tickets and details, visit trousdalemusic.com