The British girl band “Savages” perform on stage during the Roskilde Festival on July 4, 2013. (TORKIL ADSERSEN/AFP/GETTY IMAGES)

Silence Yourself,” the debut album from Savages, opens with a dialogue sample from the John Cassavetes film “Opening Night.” But a different type of cinematic gesture predicates the band’s live show: a request to please silence your cellphones.

“We believe that the use of phones to film and take pictures during a gig prevents us all from totally immersing ourselves,” read a note posted at the band’s merch table before the show Saturday night at the Rock and Roll Hotel.

Savages didn’t belabor the point from the stage, though, and many in the crowd ignored the request.

Years ago, rock bands had to contend with slam-dancers — audience members who would collide with their peers, often ruining the concert for those who did not want to get bumped. Back then, conscientious musicians asked fans not to hurt each other. Now, a band has to remind audience members that they even have bodies — and also implore fans to leave cyberspace.

Formed in London in 2011, Savages play moody and aggressive post-punk. The all-female quartet’s debut album arrived in May, but even before that, the band was the focus of music-media fawning — playing large festivals and occupying cherished front-page real estate in magazines and on Web sites.

On Saturday, the band performed a one-hour set, mostly composed of songs from “Silence Yourself.” Savages are not a perfect live band, but they possess a heavy, menacing energy. Singer Camille Berthomier — who uses the stage name Jehnny Beth — was intense and earnest, her body rigid as she barked her lyrics into the microphone. Guitarist Gemma Thompson punctuated the silence between verses with shrill feedback and woozy drones. Everybody wore black, naturally.

Savages are heavily influenced by the post-punk music of the late ’70s — bands such as Joy Division, Killing Joke and Public Image Ltd., who often ditched traditional song structures in favor of trance-inducing dirges that relied on pummeling rhythms and syncopated base lines. If that sounds familiar, it’s because the music has never really gone out of style. It has been revived so many times now — by such bands as the Rapture, Liars, the Strokes and onward — that its presence seems like a permanent fixture, like R&B or the blues.

It’s possible that post-punk is so durable because there isn’t another vessel that’s quite as adept at conveying the dark, brooding and industrial themes that are the genre’s bread and butter. So long as there are empty strip malls and apartment complexes, post-punk will never be lacking in context.

The band’s spin on post-punk is a purist, embracing primitivism, never sidling up too close to a pop hook. On record, Savages are fairly polished — but live, the members are passionate and clumsy.

All the better for that total immersion they seek.

Leitko is a freelance writer.