This is one of the most exciting jazz camps we’ve ever had,” Hosea London told the recital audience of nearly 50 in Bernheim Hall. Within moments, his charges showed why.

Crowded onstage, 15 jazz campers launched into Miles Davis’ “Freddie Freeloader” without an audible sour note or rough spot. A stout young man at one end of the front line stood for a trombone solo, followed by his saxophonist lookalike on the opposite end of the apron.

Most famous as leader of Mobile’s Excelsior Band, London is chief clinician for the Marcus Johnson Jazz Camp, a project of the 18th annual Gulf Coast Ethnic and Heritage Jazz Festival. What began as a single-day workshop in 2000 expanded to three days in 2011, when London was brought onboard.

In 2014 the event was lengthened to a full week and more instructors were recruited to support London. One of those added clinicians was Bay City Brass Band founder and leader Marcus Johnson who tragically passed away in December the same year.

Johnson’s legacy remains in more than a camp renamed in his honor months after his demise. The doppelganger soloists for “Freddie Freeloader” are his twin sons, Markel and Markes, musicians and football players at Murphy High School.

Now a two-week event, the camp takes a variety of students through the basics of America’s first original art form. The array of participants is evident in the schools they attend: Murphy, Sidney Phillips Preparatory Middle School, Spanish Fort High School, Alabama School of Math and Science, Dunbar Performing Arts Magnet School and others.

An older trumpeter said he was near completion at Bishop State Community College and aimed for music education as a vocation. He was far from the oldest.

“I’m old enough to be on Social Security,” a percussionist said to laughter from the audience. “I have a couple of sons who are musicians and after 38 years of working offshore I decided I wasn’t going to let them leave me behind. Not after I spent all that money paying for their lessons.”

London said the camp’s highlight was a July 20 field trip to the Ellis Marsalis Center for Music in New Orleans. During the visit, a jam session naturally broke out among visiting campers.

“This young lady is in her first year in our camp. She didn’t know enough to enroll last year and now we’re going to feature her as soloist on this next song,” London said as he gestured to a youngster. After her spotlight turn, she resumed her usual reticent demeanor.

“She’s just so painfully shy but something changes when it comes to performing,” Felicia Pettaway said of her saxophonist daughter, Summerlin. As illustration, the 6th grader clammed up and refused eye contact when asked if she wanted to be in a newspaper article.

“A while back she told me she wanted to go to Playhouse in the Park and start acting like her sister did. I didn’t think she would do anything at auditions but then she started singing ‘[Somewhere] Over the Rainbow’ and I started crying. I didn’t even know she could sing,” Felicia said.

The jazz campers will have another chance to impress even more locals with their new chops as GCEHJF hits full stride. The annual evening of poetry and spoken word begins Thursday, Aug. 4, 6:30 p.m. at Bernheim Hall in the Ben May Main Library (701 Government St.).

Friday, Aug. 5, features an open reception with music entitled Bicycle Jazz in the courtyard of the OK Bicycle Shop (661 Dauphin St.). It is slated to run 7:30-10 p.m. and features the work of musician Leonard Houston.

The GCEHJF main event takes place Saturday, Aug. 6, with a 3 p.m. second line parade winding from Bienville Square to The Temple Downtown (351 St. Francis St.). The Bay City Brass Band will lead participants to the venue then perform the first of five sets by various performers.

After the brass band, the jazz campers take the stage, where they will be joined by Pensacola’s Belmont Youth Band.

A festival favorite from preceding years, the combo Keep It Live follows. Guest alto saxophonist Roland Cobb will join the band’s tenor saxophonist Jarvis Wright on the front line.

Joe Occhipinti’s Big Band takes the stage shortly before 7 p.m. and headliner Myrna Clayton will close out the show starting at 8 p.m. Entrance is $10.

For more information go to gcehjazzfest.com.