The Kills make a lot out of a little

“Involving other people has always been quite complicating and confusing,’’ says the Kills’ Alison Mosshart, with Jamie Hince.shawn brackbill

For 10 years, the Kills have made the most out of the fewest components necessary for rock ’n’ roll - meaning, in the Kills’ case, a vocalist, a guitarist, and an attitude.

The duo formed in London after a chance hotel encounter between a multitalented Englishman in his early 30s with a knack for nasty, blues-rock riffs, and a decade-younger American woman who could wail to match. On the duo’s striking 2002 debut EP, “Black Rooster,’’ the sound barely added up to a one-person-band, with a drum machine completing the package.

Compared to the Black Keys and the White Stripes, two other duos making cultural wavelets back then, the Kills were even more minimalist and less rooted in tradition, like transatlantic rovers with a mechanized beat. Certainly they had the rootless rovers’ attitude down pat, romanticizing decadence and recklessness in keeping with the long rock ’n’ roll tradition that stretches from Nick Cave, to the Rolling Stones, to the image surrounding Jerry Lee Lewis, the original Killer.

In art, as in life, this deviant stance is often an obsessive dead-end, to say the least. But as the years inevitably passed, guitarist Jamie Hince and singer Alison Mosshart broadened their stance without negating its musical and emotional edginess.

In April last year, the duo released “Blood Pressures,’’ an album that at one point features a gospel choir, at another allows a tender cabaret ballad, and everywhere looks back at their walk on the wild side from a veteran’s vantage. Even so, “Blood Pressures’’ isn’t detached from that wild side - it can rock as nastily as ever - nor have the duo abandoned the singularity of their partnership. Tonight, a week before a tour-culminating 10th anniversary show in New York City, Hince and Mosshart will demonstrate that they can still do it all, alone together at the sold-out Royale.

“We both thought it was going to be really difficult live,’’ Mosshart says in a telephone interview, speaking about the new album. “I was like, ‘Well, Jamie, I can play keyboard or I can play a drum, or I can just run around stage and do nine things at once.’ We rehearsed the record for like a week, and it was, like, in two days, I think, we’d figured it all out.’’

It begs the question: Why not make the work easier by adding others to the band? But that underestimates the artistic heat of Mosshart and Hince’s partnership, a glow so hot and exclusive that it has often been mistaken for romantic ardor.

“Involving other people has always been quite complicating and confusing and underwhelming, no offense to any of those people.’’ Mosshart says, her flat Florida rasp inflected with phrasings from her long London exile. “I’m serious, though - it’s just not been what we want. Sometimes we have to re-go through that process to learn that again. Sometimes we think we can’t do it as two people, but it always seems to work.’’

Even so, the offstage intercession of other people may have helped revitalize the duo’s exclusivity of late.

“Blood Pressures’’ was released three years after the Kills’ third album, “Midnight Boom,’’ which took their original sound and stance as far as it could go. A few months after its release, in the summer of 2008, Mosshart had another chance encounter with a musical jack-of-all-trades, Jack White of the White Stripes. It quickly led to collaboration on a heavier, messier underground rock supergroup, the Dead Weather. In the meantime, Hince became engaged to British supermodel Kate Moss, whom he married in July last year.

“The Dead Weather, for me, was just incredibly eye-opening, a learning experience, a terrifying experience,’’ Mosshart says, hinting at the effect of Hince’s marriage only tangentially. “It kind of shakes up the game. And it really was good for Jamie and I to do that. I mean, I’m glad that we’re not still living in a squat, sitting there, looking at each other, surviving on toast.’’

The passion of their recommitment on a bigger stage can be heard vividly in the duet that opens “Blood Pressures,’’ the ringing “Future Starts Slow,’’ with its lines, “If I ever give you up/ My heart will surely fail.’’

Even so, for all its knowingness, “Blood Pressures’’ is looser and more expansive but ultimately no deeper than the marginally more exciting “Midnight Boom,’’ which broadened their cool leer into a gleeful grin. To their detractors’ perpetual annoyance, the duo still luxuriates in the swagger and sexiness of striking a pose. It’s the latest, age-appropriate permutation of an obsession that inspired Mosshart to abandon her life in Florida and commit herself artistically to a happenstance London acquaintance.

“People in their 20s have got all the power,’’ muses the 33-year-old about her younger self. “Your decision-making process is pretty far out. You get an idea in your head and you roll with it and there’s nothing that’s going to stop you. . . . You just do it. And the greatest things happen.’’