THE ALBUM -- Bebe Le Strange, Epic (FE 36371). THE SHOW -- At the Capital Centre, Wednesday at 8.

"Bebe Le Strange," the latest effort by sisters Ann and Nancy Wilson, is not a simple case of Heart failure. While the album has been propelled to the top of the charts, presumably by the Kristy Mcnichol generation, it's clearly not in a class with earlier imaginative hard rock by the group.

On previous albums, the Seattle duo came up with hit-bound tracks like "Crazy On You," "barracuda," "Magic Man and "Little Queen." Of course, in those days their band included lead guitarist Roger Fisher (co-author of the "Strange" title track), and manager Mike Fisher, who gave them an added emotional edge. They also happened to be the Wilsons' hearthrobs.

Since then the sisters have split from their boyfriends and Heart has regrouped. It's kept the heavy bass line and the shrill sopranos on this outing, particularly Ann's shreiking lead vocals. And Nancy fills in on lead guitar and/or drums on most cuts, but it's only pinch-hitting. The only hard rockers that measure up to previous Heart favorites are "Even It Up" and the title cut. Others stray from their proven heavy-metal formular to mournful ballad attempts that -- except for "Plot," a lilting melody -- don't ring true.

Particularly insulting is "Down on Me," seemingly a direct swipe at the memory of Janis Joplin. The title mimics an early Joplin hit; the slow arching blues number is reminiscent of another of Janis' trademark songs, "Ball and Chain." But when Ann Wilson wails the tune her desperation is less convincing than the bourbon-bottle terror that Joplin embodied. One imagines Wilson growing up sipping wine spritzers in suburbia.

The "Bebe Le Strange" title cut is a caustic tirade with charged lyrics half-spoken, half-sung by Ann Driving guitar and heavy drum support the contention that "we're all dog panicked, and you are to blame." It seems that Wilson's best when her tone is tough and accusatory, rather than anguished.

Wispy lyrics on other cuts don't tell much of a story. On "Rockin' Heaven Down," a choppy but energized tune, the words convey concert-hall excitement from the performers' point of view -- an overworked rock theme: Step into the light You're on Hook into the night That look from eye to eye A flash gets passed around A band of wild angels Rockin' heaven down They're in a rock'n'roll band on stage, see, and the song celebrates "moving their minds" -- that's their fans -- without giving the audience anything to think about. Get it?

Still, not all the slow ballads are mindnumbing. The prettiest one is the airy, soaring "Pilot," filled with jet-like guitar riffs behind a buoyant melodic display. The simple poetry meshes well with the complex musical tapestry: "Pilot I fell through/ From the blue/ I just flew/ into you." Like most songs on the album, this cut was written by the Wilsons with longtime friend Sue Ennis. But this is not the Heart generally heard on radio. And it's a shame for the pretty vocals and folk-rock melody to go unnoticed. Heart's better known for powerful, tense rock, loud and bitchy. And that's what it'll likely deliver at the Capital Centre when it shows up to rock heaven down.