When Jack White was a young, pale, skinny little boy, he misheard " Salvation Army " as " Seven Nation Army. " Years later, that happy accident has evolved into the title of the opening track on the White Stripes’ new Elephant (V2). The story gives the song an appealing air of innocence, something the older but still pale and skinny Jack and his drum-playing bandmate, ex-wife Meg White, have relied on throughout their career, which began with a homonymous indie debut in 1999 and reached a peak with their mainstream breakthrough, 2001’s White Blood Cells (Sympathy for the Record Industry), the disc that helped make Elephant one of the more eagerly awaited rock albums of 2003 (it sold 125,000 copies its first week).

On their first three albums, Jack and Meg not only embraced youthful idealism, they flaunted it in hard-hitting, riff-driven songs that planted the sexual thunder of Zeppelin in soil fertile with deep Delta blues and confessional roots music. It takes a certain mix of swagger and sincerity for a couple of white punks to draw on influences as revered as Son House and Lightnin’ Hopkins — not to mention Dolly Parton, whose yearning " Jolene " turned up on a White Stripes B-side in fine form. And they seemed to stumble on the right formula almost effortlessly. They twisted the tear-soaked blues of those artists into their own brand of Detroit garage rock — but they did so with respect, as if they were afraid to eclipse the originals (a problem Zeppelin never seemed to have).

This innocent demeanor only increased on White Blood Cells, the album that delivered them from the small Sympathy for the Record Industry to the relatively large V2. With more muscle behind them (V2 more or less broke Moby), they were able to push their first singles to radio and video outlets. The disc’s two biggest songs were the sing-along serenade " Hotel Yorba " and the raucous love paean " Fell in Love with a Girl. " On both tracks, the duo’s romantic naïveté was more than just a virtue — it was a selling point.

Elephant is where that carefully cultivated idealism gives way to fiery ambition. The title of " Seven Nation Army " may allude to Jack White’s childhood, but the song itself is a ribald, physical monster. It begins with the melodic strut of a heavy, reverberating low-end bass line. Led by Meg’s confident tom-toms, Jack coos with greaser wisdom and a live-wire imagination, " I’m gonna fight ’em off/A seven-nation army couldn’t hold me back. " After some fancy vocal embellishments from Jack, the song explodes, and whatever reverence the two once may have had for their Delta blues influences is left smashed into bottle-neck shards on the whiskey-stained floor.

That bass line — actually forged with a low-register, seven-string guitar — stands out because low-end theories have never been a part of the White Stripe æsthetic. But it sets the tone for Elephant, and the disc’s deeper, warmer bottom is a big part of what drives the album, if not in actual sound then in spirit. " Ball and Biscuit " gives Jack a chance to sermonize like a Southern-pulpit preacher, skirting between colloquial paternalisms ( " Read it in a newspaper, ask your girlfriends and see if they know/That my strength is ten-fold woman, I’ll let you see it if you want to before you go " ) and shredded guitar riffs. " Girl, You Have No Faith in Medicine " is a three-minute, up-jump-the-boogie garage stomp that has Jack playing a devilish Dr. Feelgood. The Stripes could have pulled off a similar song on any of their first three albums, but not with the thrusting confidence and unbridled energy that infuse " Girl. "

It’s not merely a new-found bombast that fuels their expanded musical ambition. Jack is at his most visceral on the acoustic " You’ve Got Her in Your Pocket, " which relies on the sole comfort of his voice and guitar, and he reveals a charismatic persona. On " I Want To Be the Boy To Warm Your Mother’s Heart, " he’s at his most intimate, confessing to his own insecurities over the forlorn sighs of a bar-room piano: " I never said I was the heir to a fortune, I never claimed to have any looks/But these kinds of things must be important, because somebody ripped out my page in your telephone book. " The broadened sonic palette (which includes the organ chords that support the pop poetry of " The Air Near My Fingers " ) gives the Stripes’ characteristic raw sound new tones and textures. Elephant thrives on these changes in method and mood, on the contrast between the rambunctious highs and the more sobering lows. It’s something the four-track, DIY approach of past recordings was never able to capture.

The expanded music horizons are matched by the duo’s expanded commercial ambition. Although Jack has afforded glimpses of his inner guitar hero on stage, rock-star aspirations have never dominated the Stripes’ image. Yet there’s been a balance between indie obscurity and the embrace of mainstream success in the way they’ve presented themselves. The cover of the White Blood Cells booklet shows Meg and Jack cowering against a wall amid a horde of what look to be painted-black journalist types. Inside, however, we see them smiling as cameras and microphones are thrust in their direction.

What emerges from this mixed message is a marketing plan that seems to have come about almost by design. Right off the bat, Jack and Meg limited themselves to guitars and drums. And rather than falling into indie rock’s anti-image irony of thrift-store stage duds, they created color-coordinated black, red, and white stage duds, which they continue to wear. There’s also the video for their single, " Fell in Love with a Girl, " which may have been conceived by director Michel Gondry (Daft Punk, Human Nature) but nonetheless played into their stylized image of childlike innocence by portraying them as figures made of Lego building blocks.

In his review of Elephant for the April 6 Sunday New York Times, Jon Pareles points out that though the White Stripes were regarded as the antidote to the pristine, commercialized pop that peaked a couple of years ago, they were just as conscious of their image as groups like ’N Sync. Back in 1999 Jack and Meg told the press that they were actually brother and sister instead of a divorced couple. That tale fed into their image of innocence as part of a loving family. The air of mystery they created only helped to raise their profile.

The two have refined their roles leading up to Elephant. She’s the quite, demure one pounding out measured backbeats. He’s the half-reluctant frontman, as flamboyant as Little Richard one minute and as coy as Jimmy Page the next. But Elephant draws him out of shell as never before: he’s at his most majestic on " There’s No Home for You Here, " where the multi-tracked vocals build up to a chorus that alludes to the rock grandeur of Queen, and he pulls off a Freddie Mercury, reaching for the heavens with operatic extravagance. On " Black Math, " he struts against a distorted wall of rhythm guitar with the theatrical cool of Marc Bolan; on the cover of Burt Bacharach’s " I Just Don’t Know What To Do with Myself, " he approaches vaudeville playfulness.

Pareles takes the Stripes to task for a back-to-basics rock style that he doesn’t feel lives up to its influences, and for being false prophets of the new rock revolution because they’re a band built on image-conscious artifice. But great rock and roll has always borrowed from its predecessors, and image has always been a part of the package, from Bowie, the Stones, the Who, and T. Rex right on up through Pearl Jam, whose image was to have no image, and the Strokes, who trade on stylized indifference. The Stripes will probably never reach the level of Son House, Lightnin’ Hopkins, or Led Zeppelin. Jack might be too obvious in his Mercury allusions. Then again, Queen never delved as deeply into the Delta blues as the Stripes do. It’s what they do with their borrowings that makes the result special.

Elephant does nothing less than feed the dream that inspires every kid who’s ever picked up a guitar with rock stardom on his or her mind. It’s a rock-and-roll fantasy where innocence and ambition mix potently. And if on past albums Jack White played up the innocence of just being a boy strumming his Jimmy Page air guitar in his bedroom mirror, then Elephant is the proof that he really wanted to be Jimmy Page all along.

The White Stripes headline the Orpheum Theatre this Sunday, April 20; call (617) 931-2000.