For the last 10 years or so, the JVC has sponsored what amounts to two simultaneous jazz festivals. Carnegie Hall serves as the big tent where headliners like Ornette Coleman, Herbie Hancock, and Smokey Robinson are featured. The shows at the smaller Kaye Playhouse are more like midway entertainments, offering intimate presentations more oriented toward older forms of jazz.

To me, these sideshows often outstrip the big events, and two concerts this week were no exception. On Tuesday night, an event billed as “Clarinet Marmalade” featured five clarinetists investigating what their instrument has meant to jazz. Wednesday evening’s show, “Ragtime to Swingtime,” was a somewhat random but highly authentic look at the jazz and pop of the interwar period.

Most of the five featured performers in “Clarinet Marmalade” took the stage for a solo set alongside a backing band of James Chirillo, guitar; Greg Cohen, bass; and Tony DeNicola, drums. But the two headliners, Kenny Davern and Ken Peplowski, stole the show.

Mr. Davern, who opened the first half, comes stylistically out of the Chicago school that produced Bud Freeman, Pee Wee Russell, and Benny Goodman and helped give birth to the swing era. Mr. Peplowski, who opened the second half, takes his inspiration from later stars such as Artie Shaw, Jimmy Hamilton, and Buddy DeFranco. Between them, the two Kens represent virtually the entire history of the jazz clarinet, and on their 2001 album, “The Jazz Ken-nection,” they complement each other brilliantly. Regrettably, they didn’t play a two-clarinet duet together on Tuesday night.

Mr. Davern’s interplay with the backing trio is exceptional. When he began his three-song set with “Oh, Lady Be Good,” he paraphrased the original Gershwin melody in his choruses, and Messrs. Chirillo and Cohen then did the same in theirs. By contrast, when he launched into a driving rendition of “Beale Street Blues,” he quickly jettisoned the W.C. Handy head in favor of basic blues playing, and the others did likewise.

Mr. Peplowski began his segment with a stunning montage of three seemingly inapposite melodies, Duke Ellington’s piano piece, “The Single Petal of a Rose,” played unaccompanied, and Lennon & McCartney’s “For No One,” and Harold Arlen’s “My Shining Hour,” with Greg Cohen on bass. Mr. Peplowski concluded in moving fashion with “A Fool Such as I,” a song introduced by the legendary Canadian cowboy Hank Snow and repurposed by Elvis Presley but rendered here as if it had been written by Billy Strayhorn.

The other clarinetists also made significant contributions. Though not as technically advanced or emotionally impressive as either of the two Kens, Evan Christopher is an entertaining player. His specialty is exploring the many connections between New Orleans jazz and the clarinet traditions of the Caribbean, which he displayed during a Latin-tinged reading of Jelly Roll Morton’s “Mama Nita” with Cyrus Chestnut on piano.

The first half ended with a duet by the festival’s founder, pianist George Wein, and clarinetist Tommy Sancton, whose day job is serving as Time magazine’s Paris bureau chief. They paid homage to Mr. Sancton’s mentor, the New Orleans clarinet colossus George Lewis, with one of Lewis’s signatures, “Burgundy Street Blues.”

The modernist Don Byron had the least technique of the five clarinetists, but his segment, which ended with John Coltrane’s “Giant Steps,” gave the show an edgy, downtown feel. His presence served to indicate that the instrument and its players are still making a vital contribution to contemporary jazz.

The show ended with Messrs. Davern, Peplowksi, and Christopher playing the main melody to Ellington’s “Creole Love Call” and Mr. Byron responding with the famous obbligato in a guttural, vocalized tone. It seemed fitting that the most modern musician on the bill should sound the most primitive.

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“Ragtime To Swingtime” was produced and hosted by Rich Conaty, whose long-running Sunday evening radio show, “The Big Broadcast” on WFUV, has introduced thousands of fans – myself included – to the music of the 1920s and ’30s. Rather than try to comprehensively cover two rich decades of musical culture, Mr. Conaty divided the show into six segments covering different themes relating to that era.

The show began with Dan Levinson’s Roof Garden Jass Band, which examines the evolution of ragtime into jazz via meticulous re-creations of the Original Dixieland Jazz Band and other groups of the World War I era. A highlight was their rendition of the raucous polyphony and animal imitations of “Livery Stable Blues.”

Next, the pianist Bryan Wright performed a solo rendition of “Girl of My Dreams” and a collage of two works by Bix Beiderbecke. These showed how the keyboard music of the 1920s can be much more mellow and contemplative that the boisterous band music of the same period.

Vince Giordano and his 11-piece Nighthawks took over for the bulk of the first set in a sequence of arrangements recorded by drummer Ben Pollack’s orchestra.They began with an energetic treatment of another Handy classic, “Yellow Dog Blues.” On “Makin’ Friends,” trombonist Dave Sager saluted Jack Teagarden with an ace impression not only of the great man’s playing but his blues singing and his trick of playing his trombone slide with a glass of water.

The second half began with another Nighthawks sideman featured in his own sub-combo, violinist Andy Stein, whose Blue Five honored the memory of Joe Venuti, founding father of the jazz violin. The fine Nancy Anderson, who is currently starring on Broadway in “Burleigh Grime$,” then showed that a theater singer can sometimes work effectively with a jazz band. She delivered a selection of three numbers originally sung by Peg La Centra with Artie Shaw’s first band, including a marvelous, underappreciated lyric by Edward Heyman, “Darling, Not Without You.”

The rest of the show celebrated another transitional swing band, the Casa Loma Orchestra, although no one mentioned that the centennial of the group’s leader, Glen Gray, came and went two weeks ago. The subset began with the Casa Loma theme, “Smoke Rings”; trombonist Brad Shigeta played the melody and Dan Block passionately replicated the clarinet solo. The band’s other clarinetist, Dan Levinson, soloed on one of the band’s killer flag-wavers, “Maniac’s Ball,” before the exceptional singer Marion Cowings delivered three hit ballads associated with Casa Loma’s resident crooner, Kenny Sargent, starting with “For You.”

The concert climaxed with the moody “Blue Prelude” and the explosive “Casa Loma Stomp.” For an encore, the Nighthawks played “Good Old Days,”(aka the “Little Rascals”theme) as Mr. Conaty made his closing announcements. I never thought I would hear Peg La Centra or Kenny Sargent – or, for that matter, The Little Rascals – re-created anywhere, let alone the JVC Jazz Festival.

The JVC Jazz Festival runs until June 24 at various locations. For more information, visit www.festivalproductions.net.