In better circumstances, the last album to feature the entire original lineup of Booker T. & the M.G.’s would’ve been a transition instead of a de facto conclusion. After nearly a decade putting out albums that boiled down to great-singles-decent-filler, a succession of big ideas — particularly a soundtrack album to Jules Dassin’s 1968 message-movie UpTight and 1970’s McLemore Avenue, a radical soul revamp of the Beatles’ still-fresh Abbey Road — brought them right up to the threshold of Al Bell’s ambitious plans for Stax in the early ’70s. The problem was that the band that’d defined the label’s sound longer than anyone still living at that point had started to dislike the new direction, and so their last real classic was cut largely outside the traditional environs of Stax’s Memphis studios. But the creative tensions that eventually split the group were put to fascinating use on Melting Pot. Some of the new artistic directions they explored during their stint in NYC’s Record Plant seem a little counterintuitive in retrospect: the Pepper Singers’ wordless bum-ba-dup pop-scat choir on “L.A. Jazz Song” and “Kinda Easy Like” seems off-kilter until it clicks how well they harmonize with Booker T. Jones’ lively B3, and hearing Steve Cropper playing acoustic (and handily outdoing “Classical Gas” in the process) makes “Sunny Monday” something of a pleasant shock. But they’re savvy risks that don’t cut into the presence of more classic-minded instrumentals like the twangy Meters-gauntlet-throw funk groove of “Chicken Pox.” And between the gospel-hued good-mood swings of mini-suite “Back Home,” the elastic dynamics of aforementioned extended vamp “Kinda Easy Like,” and the glorious build-to-euphoria rumble of the eight-minute title cut — maybe the crowning achievement of the Dunn/Jackson rhythm section, not to mention the group as a whole — whatever pressure the band might’ve been feeling found one last amazing release valve.