There is nothing subtle about Joan Jett. At the Lunt-Fontanne Theater, where she is winding up her latest tour with a five-night stand, Ms. Jett and her band, the Blackhearts, simply pounded out song after song whose titles tell their stories - ''Bad Reputation,'' ''Do You Wanna Touch Me,'' ''I Love Rock-and-Roll.''
Since she started the Runaways in 1975, Ms. Jett has been doing just one thing and doing it well - belting loud, basic, defiant pop-rock songs. Like other rockers, she sings about sex, independence, romantic strife and the radio, demanding for herself all the raunchy prerogatives bad-boy rockers have long taken for granted.
While feminism's advances make her seem less daring now than she was a decade ago, her songs have not lost their satisfying crunch. On Thursday, Ms. Jett, in white leather, sang in a hoarse shout as she snapped out rhythm-guitar chords; the Blackhearts, augmented by a keyboardist and the Uptown Horns, kicked and stomped behind her with the impact of pure, familiar formulas.
Ms. Jett has defined her own version of a rock mainstream, in a line from Chuck Berry and the Rolling Stones to the Ramones and AC/DC. She does not care where a song comes from as long as it has the right sound and attitude. Her carefully chosen cover versions embrace punky cult items, a lesser-known Chuck Berry song and obscure 1970's glitter-rock alongside million-selling 1960's hits. And her own songs alternate snarls and come-ons in a way that she perfected for her 1988 hit ''I Hate Myself for Loving You.'' Again and again, Ms. Jett proclaims her desire and desirability, on the condition that she gets as much as she gives.
Good as the music was, Ms. Jett's Broadway stint raises consumer questions. For $25, nearly twice the price of an equivalent show at the Ritz, listeners got comfortable seats, a clear sound system and a program (in which the notes rewrite history by calling the Runaways ''the first all-girl rock-and-roll band,'' ignoring Fanny). But the band played for barely more than an hour.