Mostly Other People Do the Killing obliterates the boundaries of jazz

“We believe that we are completely, straightforwardly a jazz band,” says bassist Matthew “Moppa” Elliott. “With no qualifications at all.”

Why is this a question? Well, listen to any of the four studio albums by Elliott’s genius group with the oddball name Mostly Other People Do the Killing, or witness its kinetic, eccentric stage show, and you’ll understand why, in the nine years this New York quartet has plied its craft, queries have arisen.

Are they mad archivists, omnivorous consumers of riffs from swing, bebop, avant-garde, 1980s funk, classic rock, smooth jazz, and more, with a propensity to regurgitate these contents at unexpected moments and in strange ways?

Are they attention-deficit virtuosos of the avant-garde who get their kicks from the honks, squawks, or drones that ensue when, for example, trumpeter Peter Evans and saxophonist Jon Irabagon depart on a digressive duet that feels like two bulls with horns interlocked in struggle?

Are they jesters who send up the canon with tricks like drummer Kevin Shea’s solos, which might find him dismantling the drum set, crawling on the floor, or staging an impromptu puppet show? And what’s with the song titles, nearly all of which refer to obscure, oddly named towns in Pennsylvania?

Answers are best found live, as on Sept. 27, when MOPDTK plays the Institute of Contemporary Art, on a hip double bill with avant-garde guitarist Marc Ribot. But Elliott, who composes most of MOPDTK’s songs and might be considered the band leader — if only they believed in leaders — offers clues to the method behind the madness.

“You need both,” Elliott says, referring to jazz repertoire and the daring, no-boundaries experimental music that are usually presented in opposition. “Someone needs to be playing Duke Ellington tunes, straight up. And we also need people not doing it. Neither one is more important than the other.

“The form our insurrection takes is we’re just trying to provide this alternate view of the whole situation, where you don’t need to worry about reverence and irreverence. Everything is fair game and everything is portrayed in a positive light.”

Exhibit A is, well, pretty much any MOPDTK song — “Blue Ball,” for example, on the 2010 album “Forty Fort” (both places in Pennsylvania, Elliott’s home state). It contains bits of bossa nova, New Orleans, way-out group improvisation, and a lusty reprise of the chorus from Sheena Easton’s “Strut.”

Exhibit B is the stage performance, where any boundaries still left standing fall away, Elliott says.

“When we play live, two or three songs could be happening simultaneously. Or we could stop in the middle of one song and go straight into another. The tunes from our studio albums have become the book; we can jump in and out of them quickly. It’s like a kaleidoscope: It could be fragmented or unified, and change in the span of two or three seconds.”

To pull this off entails meeting a few requirements. First, of course, is virtuoso command of a massive repertoire of music and ideas, and the creative curiosity to sustain it. Second is an extreme level of trust and comfort with one’s bandmates. MOPDTK, who don’t take a gig if all four players can’t make it, have this kind of entente.

“Any one of the four of us can literally do anything we want, whenever we want,” Elliott says. “If any one of us goes off on a tangent, it’s fine. We know that whatever the outcome is, we have ways of bailing each other out — or not. We’re comfortable.”

Just as important to MOPDTK’s effectiveness is that as brainy as their process is, their performance is joyous and their music is accessible. There’s no obligation to pick up on the references. And there are plenty of swinging, melodic passages, without which, Elliott says, the excursions into weirdness would lose their point.

“It wouldn’t work if we were just playing complete chaos all the time,” he says. “It’s the fact that out of chaos it’s suddenly some crisp 4/4 swing for 30 seconds, then it’s gone — the contrasts are what make it interesting, hopefully for the audience, too.”

MOPDTK gets its name from a quote attributed to Leon Theremin, inventor of the early electronic instrument that bears his name, and a survivor of the Soviet gulag. He is said to have exonerated Stalin because “mostly other people did the killing.” “That was the darkest thing I’d ever heard,” Elliott says, and therefore a good band name.

But the name reads just as well as an inside joke about jazz’s many sub-streams that unite in the timeworn expression of high praise for a show, album, or solo: “That was killin’!”

At the ICA show, Elliott says MOPDTK will partly try out new material that draws on yet another territory: the much derided fare known as smooth jazz. The band has been beefing up on Grover Washington Jr., David Sanborn, and other smooth-jazz icons, in the belief that they, too, have expanded the jazz language in ways that all the synth-heavy production of the time hurt, but didn’t kill.

“What’s interesting is all the weird scoops and swells and turns in smooth jazz,” Elliott says. “As an ensemble, we’re delving into that stuff. It ended up generating what for us was very useful, in that our new tunes don’t sound anything like the tunes that we already have in our book.

“And so it opens up new territory that we can spontaneously invade.”

Siddhartha Mitter can be reached at siddharthamitter@gmail.com.