Up to this point in the career of Sleater-Kinney, their music has been its own sealed-off universe: you’d be hard-pressed to pin down their influences, and they’ve been unencumbered by conspicuous imitators. We’ve been accorded the luxury of coming to know them on their own terms, and by now we’re familiar with the way they work. Corin Tucker rushes bullishly in, rusty power chords blazing, and spills her guts in a shrill, messianic howl. She’s a mess and she’s beautiful and she knocks over all your stuff. You hang on every word. Then Carrie Brownstein tiptoes in behind her, wiry and fidgety, picking meticulously at needling clusters of notes and neatening up as she goes. Brownstein is the protector: you get the feeling that if you said something mean to Corin, the next thing you’d see is Carrie’s fist. (Best example: back on Dig Me Out’s "Not What You Want," Tucker, in the middle of an exorcism that would appear to be consuming her, wails, "TELL ME BABY, WHAT’S WRONG?" You’re riveted, and then you feel an elbow in your ribs, and it’s Brownstein, scowling: "She’s on fire. You think you wanna watch. I think you better not.")

And if you felt after 2000’s All Hands on the Bad One that Tucker, Brownstein, and drummer Janet Weiss could pretty much keep it up forever, you will likely be relieved to see them let loose on their One Beat (Kill Rock Stars). It finds them playing for kicks and, for once, freely borrowing ideas and melodies from second-hand sources without taking too much care to cover their tracks. In fact, this time around they go out of their way to point out what they’ve stolen. I don’t think of Sleater-Kinney as being any more (or any less) brave for having written a song that dares to suggest that all this post–September 11 patriotism is a bit patronizing. (I’m sure all those Republican hawks who bought Call the Doctor will be real broken up about it.) But it takes a certain irreverence to write a protest song with a martial dub-reggae foundation, to sing it in the King’s English, and to call it "Combat Rock." It’s also my opinion that anyone who cops the "woo-woo" backing vocal from "Sympathy for the Devil" on a song called "Sympathy" is either a bad-ass motherfucker or someone whose lawyer is a bad-ass motherfucker. The Clash? The Stones? Others have touted Sleater-Kinney as the best rock-and-roll band in the world, but this is the first time they’ve tried the uniform on for size.

Not all of One Beat fits: "Step Aside," their attempt at a call-and-response agit-prop party jam ("Why don’t you shake a tail for peace and love?"), suffers from a strangely formal stiffness and a horn section that’ll probably make ’em wince five years from now, if not sooner. But part of the appeal of this release lies in listening to the ladies revel in a little well-earned self-indulgence. And often it pays off. The exclamatory "Oh!" is their most ecstatic love song since "I Wanna Be Your Joey Ramone," not to mention their most explicit girl-group homage yet: it’s got three-part beach-pop harmonies, its surf-twang guitar is equal parts Go-Go’s and Bangles (if you find yourself humming "Walk like an Egyptian" over the verse, no one will stop you), and toward the end they sneak in a handclap breakdown straight out of the Crystals’ "And Then He Kissed Me."

One Beat is Corin Tucker’s first album as a mommy — to the fabulously named Marshall Tucker Bangs, born in March of 2001 — and motherhood will, I think, do wonders for her prowess as a songwriter. It’s a role she’s been auditioning for since at least Dig Me Out’s "Little Babies," perhaps the first song ever to employ housewifery as a metaphor for pop stardom. In that song at least, it didn’t seem a role she was particularly enthused about, unless peeling potatoes is your idea of rock-and-roll fun. But it’s a role she takes to here with relish and terror and wonder. Her voice is an instrument built to sound an alarm, bold and brassy and shaking like a rung bell. Once in a while you wish she could turn it off, could sing something, anything, without its sounding like a matter of life and death.

On One Beat she sings a pair of songs that are in fact about matters of life and death, and they are terror incarnate. Not once but twice on this album — once at the beginning and once at the end — Tucker begs for her son’s life. The first time, on a song called "Far Away," it’s 7:30 Pacific Time on the morning of September 11, 2001, and she’s nursing Marshall on the couch. The phone rings, she turns on the television, and the world, or the version of it we thought we knew, is coming to an end.

Although the song is called "Far Away," Tucker perceives the danger to herself and her young son to be quite close, as all of us must have in those hours, and the title seems part of her effort to put some distance between the ugliness of the day, the ugliness it stirs up in her breast, and what remains of her conscience. She takes a shot at the nation’s CEO in a line about a president’s being in hiding while "working men rush in to give their lives." But then in the last verse, her self-righteousness crumbles into a cry for mercy. And forsaking her worries about presidents and working men and the enemy, she asks God or whoever’s up there to spare her loved ones — "I look to the sky/And ask it not to rain/On my family tonight" — not to spare us all, not to spare her friends, and perhaps, from the sound of her voice, not even to spare herself.

I would like to think that the effect is intentional, and that what she’s getting at here is the futility of self-righteousness in the face of tragedy. What interests Tucker about September 11 turns out to be less political than personal: the way that in our darkest moments, fear turns us inward upon ourselves and drives us out of the world — atomizes us, reduces us to our smallest trembling pieces. "There is no righteousness in your darkest moment," she sings on the album-closing "Sympathy." "We’re all equal in the face of what we’re most afraid of." The humility of those lines is profound and hard-wrought, and she sings with a powerful conviction, in the barely restrained hysterical cadence of a street preacher.

Once upon a time, on the album that introduced Sleater-Kinney to the world, Corin Tucker called for a doctor. But as "Sympathy" begins, there’s one already present, and she doesn’t like the look on his face — the details are sketchy, but we can surmise he’s given her bad news, and that the bad news relates to her son. The crisis occasioned by this mysterious diagnosis sweeps Tucker from the footloose frenzy of the rest of the disc back to the emotional minefield of "Far Away." "Sympathy" is an elegy, a devotional, a plea, and an apology. "I know I come to you only when in need," she begins over a creak of rusty slide guitar, "I’m not the best believer, not the most deserving." And then she gets down on her knees and begs God not to take her son from her while the Stones’ old sympathetic "woo-woo" builds behind her, shrill and taunting. She tries to reason with God; she is transformed, laid "naked in the face of death and life." When she offers an apology "for those who didn’t make it/And for the mommies who are left with their heart bleeding," it’s almost as if she were repenting for the sin, though it is no sin, of having prayed for the safety of her family on a day when so many lost so much. Such is the awful, desperate love of mothers for their sons, and their songs.

ALMOST A DECADE after Sonic Youth introduced their audience to Nirvana on the tour captured in the film The Year Punk Broke, Sleater-Kinney introduced their audience to a virtually unknown candy-striped blues-punk duo who’d just released their second album on the overextended garage-punk label Sympathy for the Record Industry. SFTRI released scads of albums and sold them to a small niche market that hadn’t really been a part of the indie-rock diaspora since the early ’80s. So it was not at all a foregone conclusion that the White Stripes would end up on MTV; they might easily have lived out their careers as the toast of garage punk’s low society and never found a wider audience. Their ticket out of the garage-punk ghetto was opening for Sleater-Kinney: the buzz spread virally from town to town in the year 2000 along the tour route, and by the time White Blood Cells hit shelves, the Stripes were poised for a breakout.

By their own choice, Sleater-Kinney may never break out of the indie-rock ghetto — a larger ghetto than garage punk, but still a closed system — yet they have the ear of an audience that is just big and varied enough to carry the news of the underground to the mainstream. When S-K hit the Roxy October 14, they’ll be bringing with them the Yeah Yeah Yeahs, a garagy New York City trio who’ve already kicked up a buzz after having released a grand total of six songs, five of which appear on the debut EP that’s just been reissued by Touch & Go. (Six songs might not sound like much, but remember that when the Strokes got signed, they’d released only three.)

The EP was recorded by downtown art-punk hero Jerry Teel, who’s been kicking around since the heyday of the Lower East Side sleaze-noise scene in bands like the Honeymoon Killers, the Chrome Cranks, and, more recently, the Knoxville Girls. It’s no surprise, then, that the Yeah Yeah Yeahs’ best song, "Bang," sounds like vintage Jon Spencer/Boss Hog, with a loping, heavily reverbed guitar lick, an unfathomably funky trashcan backbeat, and a sexually explicit vocal hook that Pussy Galore would’ve killed for. "As a fuck, son, you suck," sneers frontwoman Karen O, to whom size definitely matters ("the bigger the better," she pants elsewhere). What makes the song more than just a novelty is the rest of Karen O’s delivery: her voice mostly shudders through clenched teeth, as if she were on the verge of either a breakdown or a restraining order — imagine the PJ Harvey of "50 Foot Queenie" squeezed into the Corin Tucker of "Call the Doctor" and you’re halfway there. Sex and violence haven’t gotten along this well in years.

Sleater-Kinney and the Yeah Yeah Yeahs will play the Roxy October 14. Call (617) 931-2000.