If you walk down Washington Road most evenings, you’ll hear footfalls of joggers, dogwalkers and the tail end of traffic as the sun sets. Walk past Washington Road’s St. Paul’s Episcopal Church some Thursday evenings, though, and those familiar noises begin to mingle with the sounds of trumpets and trombones wailing, a crooner singing Sinatra and the tuning of an upright bass.

Thursday is rehearsal for The Jazz Conspiracy, a 17-piece big band based in Pittsburgh. The group’s style harkens back to the days when jazz and swing dominated America’s dance floors, playing tunes made famous by such artists as Stan Kenton, Cole Porter, Irving Berlin and Frank Sinatra mixed in with more current big band pieces and a few original compositions. The Jazz Conspiracy uses the instrumentation standard among big bands of the 1930s, ’40s and ’50s, featuring two vocalists, five saxophones, four trumpets, four trombones, a piano, a bass, a guitar and a drummer. While The Jazz Conspiracy records its music and posts it online, recordings don’t quite capture the complex sound this large group creates in live performances.

“[Big band and jazz] used to be the soundtrack of people’s lives, the music they celebrated and fell in love to,” says trombonist Paul Martin, Connecting Road. “[It] was not just connected to the pulse of everyday life; it was the pulse itself.”

“It’s the purest American art form,” says trumpeter Doug Reichenfeld. “Big band and jazz were created here…and it’s pretty fun to play.”

The Jazz Conspiracy got its start last November as a small reading band, or a group of musicians that primarily meets to sight read and rehearse music, organized by baritone saxophonist Dan Lindey through Craigslist. The members soon realized there was enough talent among them for a real band and recruited other musicians to complete the roster. Last March, the group began performing as The Jazz Conspiracy.

Big band music allows skilled players to both collaborate and solo. “There’s harmony among players in each section and specific parts of the music and in the band overall that makes playing this type of music thrilling and rewarding for so many musicians,” says Lindey, a music teacher in North Allegheny schools.

The Jazz Conspiracy features musicians ranging from age 23 to nearly 70, all with varying degrees of professional music training. A tax lawyer by day, Martin, for example, describes himself as a “product” of Mt. Lebanon School District’s music programs. He names former Mt. Lebanon High School stage band director Phil Bianco and trombone teacher Harold Steiman, a Mt. Lebanon resident formerly with the Pittsburgh Symphony Orchestra, as influential figures in his musical education.

Members of the Jazz Conspiracy hail from as far as Liverpool, England, where vocalist Pete Curtis grew up, but Martin isn’t the only one with local roots. Reichenfeld, Fieldbrook Drive, is an elementary music teacher in the Mt. Lebanon school district. Although he plays the trumpet in The Jazz Conspiracy, Reichenfeld teaches all the instruments as an elementary band instructor.

Trombonist Frederic Casilli, Lemoyne Avenue, also taught music in Pittsburgh Public Schools. The senior member of the band, Casilli grew up in Brookline, graduated from Duquesne in 1963 and served in the Army, where he played in both Army and NORAD bands.

“My first teacher was Jack Purcell, a former member of the Pittsburgh Symphony,” Casilli says. “I started playing in his dance band at age 16 and had to join the Pittsburgh Musicians’ Union to do so.”

St. Paul’s Episcopal Church hosts The Jazz Conspiracy’s biweekly rehearsals, a location Martin says the band chose because of the church’s good music program and excellent acoustics. The group will perform there at 3 p.m., on Sunday, November 11, as part of the church’s Friends of Music Guild Concert Series.

For more upcoming performances or booking information: TheJazzConspiracy.com or daniel.lindey@thejazzconspiracy.com.