The only thing reminiscent of a “Circus” in Britney’s sixth studio album is her low, husky, almost lion-like growl. Unless your vision of a circus includes lascivious Britney strutting her “six-inch heels” and scanty “lace and leather” garb intoning: “all eyes on me / in the center of the ring.” In that case, this is Britney’s Barnum and Bailey’s. Bitch.

“Circus” is shameless and defiant like walking into a gas station bathroom without shoes. Even if perpetually stranded between southern bell and wild thing, Brit can still put on a show.

This album is also noisier, cheaper and decidedly wilder than her previous efforts. If there was any doubt still left in your mind, Britney has ditched her media-darling innocence of old. Auto-tune processing, megathumpy beats and mechanistic synthesizers all evoke an artist tirelessly jumping through modern pop-queen hoops. With exhausting repetition in the refrains of almost half her songs (“Glass, glass, glass, glass/ like, l-like, like … glass / glass), she sounds like a dying fembot.

There are some entertaining stints. “Womanizer” is destined for temporary club music stardom with maybe half the shelf life of “Gimme More.” The title track, meanwhile, is surprisingly not ridiculous. With its dynamic, multi-octave vocals and tasteful electronic accompaniment, it reveals some of Britney’s former pop eclat.

“Circus” is raucous fun, if something of a flimsy tent act.