3 generations of rockers: Is it 'Loud' enough for you?

"Three of us get together, what's gonna happen?" asks Jack White ominously about "The Summit" he has been invited to attend with fellow guitar heroes Jimmy Page and The Edge. "Probably a fist fight," he figures.

Yeah, that White is a dramatic one, a neo-primitive, blues-infused rocker from Detroit who relishes leaving blood on the strings – and has the smeary messes to prove it.

But his Summit partners in the new rock doc "I Might Get Loud" are different sorts.

The Edge, janglemaster of Ireland's supergroup U2, is a perfectionist and a tad neurotic, who wakes up some days fearing he's burned-out or clueless, and is constantly, endlessly tinkering with the technology of his guitar sound so that, like snowflakes, no two songs appear exactly alike.

And then there's Mr. Page, an architect of Britain's truly legendary Led Zeppelin band, who has grown into a country gentleman of quiet confidence. He knows he can play practically anything because, well, at one time in his life, he probably did.

The thematic hook of the movie is a get-together on a sound stage, one day in January 2008, where stories are to be shared and musical sparks should fly - if not fists.

What we get is not nearly as explosive as the title intimates, but a lot more durable, as directed by the man (Davis Guggenheim) who sold us on Al Gore's "An Inconvenient Truth" and produced by a music-loving studio chief (Legendary Pictures' Thomas Tull) who envisioned the project and gave it wings.

While sometimes moving sideways, to throw us off the scent, the project eventually reveals itself as the intertwined biographies of three distinctive and gifted rock guitarists, guys who truly love their work.

Fans are gonna love the in-your-face perspective, as we globe-hop with Jack, James and The Edge from childhood haunts to concerts to creative retreats. Along the way, each is encouraged to pull out favorite records and early original music, home movies and first appearances on the telly. All to help us intuit, when they can't precisely find the words, how each became obsessed with music.

It helps that each of the three guys comes from a different era and musical mind-set, allowing for a whole lot of nonrepetitive lore and history to seep through, broadening the cast of characters and big picture.

Page, the elder (at 65), delights in recalling the easily mastered skiffle music of Lonnie Donegan and primitive guitar warble of Link Wray that was inspiration for him and other British Revival-era notables of the 1960s.

Our (48-year-old) middle child, The Edge - known to mum and dad as David Howell Evans - takes us back to his secondary school and pulls out early cassettes to suggest how ambitious and at the same time underprepared U2 was for stardom, though they surely grew into their clothes.

And then there's 34-year-old Jack White (born John Anthony Gillis), the youngest of 10 (no wonder he's scrappy) and the most colorfully portrayed of the three. A devotee of primitive blues men like Son House (and sometime sidelining actor), White proves the point that you can make music with just a couple nails, a board and a string. Or make it big with your White Stripes sister Meg banging away on the drums.

Eventually, the three do get around to playing a couple tunes together, finding unity in a bottlenecked blues and "The Weight" of The Band. By this time, your ears and gut are already so full of music that the long-awaited "Summit" comes off as just dessert.

Produced by Peter Afterman, Davis Guggenheim, Thomas Tull, directed by Davis Guggenheim, distributed by Sony Pictures Classic.