There are three phrases Elise Testone repeats often when she’s teaching her vocal students. Sitting at the keyboard in her tiny Styrofoam-walled office, she reminds 14-year-old Ellie Buchanan of the most important one: “Picture that string pulling your spine up to the ceiling.” Buchanan, standing 18 inches away, hands clasped in front, as if reciting the Pledge of Allegiance, stretches upward and follows Testone through the vocal warm-up: “E-E-E-E-E-E-E.”

When Testone’s not romping around on stage leading the Freeloaders or hosting one of her James Brown Dance Parties, she camps out in this cubicle-sized mini-studio at Music Unlimited in Mt. Pleasant. She uses her expert vocal abilities to teach 20-some students, ranging in age from six to 60.

“When you sing the E, you have to tighten up the corners of your mouth,” she instructs Buchanan, making the motion herself. After the next line of warm-ups, she delivers the second of her phrases: “Try to sing more like your regular talking voice.”

A John Coltrane poster hides behind an amp, and tangles of wires and laptop chargers intermingle with a Frank Sinatra songbook. After a slight knock on the door where the students’ heights are marked, the next pupil, 16-year-old MacKenzie O’Brien, pokes her head in.

The supremely confident O’Brien is all business as she and Testone make buzzing sounds in unison. After warm-ups, O’Brien fingerpicks her guitar and sings Adele’s “Daydreamer” as Testone records video on her laptop. On the lyric sheet, Testone blocks out where she should be taking breaths. “This part starts to break down in pitch because of your breathing,” she says. “So after this line, fill up your lungs. Try it again from the last part.”

O’Brien starts where she left off, focusing on her breathing. While it sounded good before, that breath is key, and the next line comes out with strength and truer pitch. Testone does this multiple times in every lesson: proposing a small adjustment whose efficacy is immediately felt. This is not an accident; it is the accumulation of years of study.

Growing up in New Jersey, Testone’s father collected jukeboxes and was “always working on them in his workshop, playing the records really loud. Motown, the Beatles, blues, soul.” This fact is not lost on the readers who voted the Freeloaders Best Funk/Soul/R&B band.

“I was always very quiet,” Testone says. “But one day, my friend’s mom heard me singing in the car and told my mom, ‘She could really sing.'”

Testone started lessons and, at 13, became the youngest student New York City vocal coach Judy Hages had ever accepted. The time with Hages was monumental. “We would record all the lessons,” says Testone. “I noticed a huge change in my voice, and in a short time, I just understood it.”

Watching her teach, her knowledge of the singing process is obvious — how each body part connects to the others to create the desired sound. Masters of anything — singing, dance, badminton — make it look easy, as if they simply open their mouth and beauty comes out. But achieving that effortless quality (which Testone has) takes years of immense effort.

As O’Brien hangs on the last note of “Daydreamer,” Testone busts out a huge smile. “Everything’s so, so good,” she says. “Just the one part, that ‘will’ wants to go flat when it’s too breathy. But you got me on the ‘waiting.’ I almost cried.”

Her genuine happiness for O’Brien is touching. There’s no note of self-congratulation there; it’s the happiness of a friend seeing another friend do something beautifully.

O’Brien stays late to sing Amy Winehouse’s “Valerie” with Carrie and Gracie Rosene, the next two students. All three sang it at one of Testone’s summer concerts at the Village Tavern (Testone and the band also recently paid tribute to Winehouse, performing Back to Black in its entirety at the Pour House). O’Brien’s parents wanted to hear it, too.

It was an odd scene: seven people squeezed into a windowless hole smaller than most Mt. Pleasant closets so these students could sing one song together. It was fantastic. They loved it and sang their hearts out. O’Brien and her parents said goodbye as Testone turned to the Rosene sisters: “Allright, warm-ups.”

On stage at her own shows with the Freeloaders, Testone’s voice shifts instantly from soft to dangerously Joplin-esque. Her unpredictability intertwines with guitarist Wallace Mullinax’s similarly striking and powerful playing. Their melodies and riffs float over the low-down nastiness that bassist Oliver Goldstein and drummer Jack Burg create. The guys from the Freeloaders regularly play around the Lowcountry as a trio calledThe Dead 27s, too.

The Music Unlimited students will perform at the Windjammer Oct. 28-29, where, Testone explains, “The parents drink and the kids eat chicken fingers and …”

“Fried pickles!” interrupts Carrie Rosene.

“Oh yeah, I love fried pickles,” says Testone. “You love fried pickles too? Oh, I love you guys!”

Carrie, 16, has been taking lessons for three years, and Gracie, who’s 13, joined last year. They revel in Testone’s company (she’s taking them Halloween shopping this week) and seem like they’ve been waiting all day for this. So does Testone.

Gracie brings in a few Twizzlers from the front waiting area. They’re the good kind, twist and peel. During warm-ups, Testone looks at her: “I hear her more than I hear you. Do you have Twizzlers in the throat?”

“Umm-hmm,” is the sheepish reply.

“Me too,” admits Testone. “That was a bad idea.”

Carrie plans to sing the Cranberries’ “Dreams” (she channels Dolores O’Riordan with surprising conviction) at the Windjammer show, and she sings the high notes over Testone’s strumming guitar. There’s not much to work on.

Gracie starts her song, Paramore’s “Decode.” “That’s one of the best starts you’ve ever had,” says Testone, adding her third-most common phrase: “When you’re singing, don’t think about us. Think about the words you’re singing, what they mean.”

“I feel like I’m still thinking about Twizzlers,” quips Gracie.

On a long bending note on the word “know,” Testone reaches over and gently pushes Gracie’s stomach in. Her voice immediately reaches higher, and she nails it. It’s a testament to Testone’s knowledge of the body math so integral to singing, but also to Gracie’s comfort with Testone to let her poke her in the stomach, keep singing, and just let it help her.

“That was great. That’s the most I’ve ever heard you sing out!” claps Testone.

“Me too,” Carrie chimes in. “You sound good.”

Gracie smiles with a mischievous shyness and says, almost laughing, “I really want another Twizzler.”

“Go get one,” says Testone. “You deserve it.”