There’s an old Groucho Marx routine in which he points first in one direction and then the other and says, “You go that way, I’ll go that way, and we’ll meet in the middle.” The Dirty Dozen Brass Band, which will appear at B.B. King’s on Friday, is essentially a funk band with jazz elements, whereas the World Saxophone Quartet is an avant-garde jazz group that occasionally channels its collective resources into a pop project. Now, like Groucho says, they are meeting in the middle: New albums from both groups cover very similar ground, using forms of the blues and soul music to express a political and cultural protest.

The idea of using music as a vehicle for protest is a tradition not of the “art” music world, of classical and modern jazz, but more of the vernacular world, of blues and blues-derived pop (not to mention calypso). Jazz musicians only began routinely expressing their dissatisfaction with the state of things in the rebellious 1960s (Charles Mingus was one of the first), when the shrieks and screams of free jazz were interpreted by many as cries against a perceived racist and imperialist establishment.

The Dirty Dozen Brass Band, which was formed officially in 1975, was spawned by the evolving tradition of New Orleans parade bands. In New Orleans during the 1950s and ’60s, younger musicians working with established brass bands gradually introduced the newer rhythms of rhythm-and-blues into the parades and marches. Since the classic 16th-note triplet rhythm of R&B was essentially born in New Orleans, this was a natural and inevitable development. By the time the DDBB recorded for the first time in 1984, it had perfected an idiosyncratic blend of funk and jazz played by the traditional New Orleans parade instrumentation, with several mobile percussionists instead of one trap drummer, and with Kirk Joseph doing on sousaphone (the marching version of the tuba) what a studio funk master like James Jamerson did on Fender bass.

Thirty years after they first came together, most of the eight members of the DDBB lost their homes when the levees broke in the aftermath of Hurricane Katrina. They have responded to the crisis by recording a new interpretation of “What’s Going On?,”Marvin Gaye’s classic soul album of 1971. That year, Gaye was protesting not only the war in Vietnam and the decimation of the environment, but the restrictive treatment of artists at Motown Records. Under the iron-thumb rule of founder Berry Gordy, singers were not permitted to have any say in their musical destinies and any kind of protest music was strictly prohibited. Gordy refused to release “What’s Going On” at first, but when he did, the album was lauded as the finest of Gaye’s career and one of the great soul albums of all-time.

The DDBB’s re-purposing of “What’s Going On?” is a potentially dicey proposition: Although half a dozen composers contributed to Gaye’s 1971 masterpiece, the album flows seamlessly, both like a concept album and like a song cycle. It’s a short, 35-minute LP in which the individual songs run in and out of each other, like a single statement in nine sections. Further, even though Gaye was railing against what was happening to the environment and the escalation in Cambodia, he delivered his disapproval in the soft, soothing tones of Motown soul — this was protest music that you could make out to. By contrast, the DDBB makes music with a martial swing, the kind not for making love to but for a million men to march to. The group’s take on the nine songs is considerably darker and funkier. It’s also largely instrumental, although three guest vocalists do appear. (I’m not sure if rapper Chuck D. qualifies as a vocalist, but his statement on the opening title track is highly musical.)

On “Save the Children,” one of the original album’s most arresting tracks, Gaye delivered the vocal simultaneously on two levels via multitracking: first as a preacher, outlining the words of his sermon to the congregation in a calm, dry tone, and then singing them in a sweet, impassioned voice. The DDBB’s version is one of its more mellow performances, in which the two voices of the original are represented by a romantic baritone sax solo by Roger Lewis, which is contrasted by an altissimo shriek from the tenor saxist Kevin Harris over a street parade backbeat. This is appropriate music for the late show on Friday the 13th.

Meanwhile, for its new album, “Political Blues,” the World Saxophone Quartet outfitted itself with guest stars such as the trumpeter Jeremy Pelt, the trombonist Craig Harris, and a rhythm section (contrary to their usual policy of using just their four saxophone-playing members). Here with drums, electric bass, and guitars, the WSQ at first sounds a lot like the DDBB — especially on the title track, delivered in a Bourbon Street marching tempo. This opening salvo also shows composer-tenor saxist David Murray to be a surprisingly convincing vocalist, delivering his lyrics in a style halfway between rapping and traditional blues singing.

A formidable slice of the latter is supplied by the space-age electro-bluesman James Blood, providing a post-nuclear update of Muddy Waters’s “Mannish Boy,” the only cover on the new album. Many have grown accustomed to the WSQ’s usual sound — a distinctly postmodern saxophone section playing by itself bereft of brass or rhythm — but with the additional instruments, the group sounds like it would be right at home playing a parade in New Orleans. This is the WSQ’s funkiest project yet.

On the whole, “Political Blues” is far more confrontational than either edition of “What’s Going On.” Particularly scathing is “Bluocracy,” in which Mr. Harris attacks “so called traditionalists, neos, and so-so’s,” whom he characterizes as “a 21st-century modern minstrelsy.” This too, is an old argument, a polemic that has been waged in jazz since the bebop era. Although Mr. Harris blasts musical conservatives for trashing “40 years of hard fought for advancement,” much of the vocabulary of the album is rooted in both the soul music and the avant-garde jazz of the ’60s and ’70s. The WSQ’s combination of these two disparate forms results in a pertinent contribution to what Mr. Harris calls our “our ever-evolving innovative history.”

Whether you characterize either album as highly ambitious pop or especially accessible modern jazz, both “What’s Going On” and “Political Blues” are the kind of protest music that, far from dragging us down, lifts us up and makes us see the light.