It rocks hardest when it gets quiet

When it’s nearing midnight and some amazing maniac is shredding through a guitar solo on stage, eyes closed, sweat flying, vibrations rumbling through the house like a northbound freight train, it’s easy to forget just how much art and craft and science is involved in creating that sound.

Director Davis Guggenheim, who brought us Al Gore’s “An Inconvenient Truth,” reminds us of this in his very fine documentary about the electric guitar and the men who play it best, “It Might Get Loud.”

Following three generations of rock virtuosos -- Jimmy Page, the Edge and Jack White -- on a journey through time, the film takes us behind the scenes as these artists talk about their relationship with and philosophies about that curve of electrified sound they have each mastered in distinctive ways.

The film culminates as the three finally come together on an empty soundstage in Hollywood for a conversation and a raucous jam session that is remarkable for its intimacy and its passion.

But the story begins more simply in a pasture as White, the creative force behind the White Stripes, the Raconteurs and the Dead Weather and youngest of the three, builds a guitar out of fence wood, a Coke bottle, a few nails and some twine. You can make a guitar out of anything, he tells us, as he turns this crude but playable instrument over in his hands.

Like with the others, there is a love affair going on here. They’ve been seduced by the powers of the instrument to reach something inside that emerges in a sound that flows through an amp and grabs the rest of us. The emotion coursing through the tangle of wires, and increasingly versatile amps, is sometimes raw, sometimes soft, but always alive.

We get a look at the transformation of a simple chord progression as U2’s the Edge seems to split and then, with the twist of a knob, amplify, creating the delay-echo effect that is his signature. When, in another frame, we’re put in the middle of the band’s performance of “Sunday Bloody Sunday,” as the echo of his guitar rises and falls, distinct from the whole, you process it differently.

Guggenheim does a good job of capturing their craft rather than the rock star side, trailing them on their home turf, away from the crowds. Page -- who formed Led Zeppelin, with Robert Plant as its vocal powerhouse, after the Yardbirds fell apart -- rummages through his massive vinyl collection, talking about the sounds that influenced him.

For nearly a year, the filmmaker followed the three, going back to Page’s estate near London, to the Dublin classroom with the Edge where U2 practiced when they were still just ordinary schoolboys, to Austin and Nashville with White.

Among the pleasures of the film are the old snapshots, particularly of Page and the Edge, capturing them before fame came in waves of screaming fans. Or hearing rare performances by those who influenced them, such as White explaining his immediate connection to the old blues man Son House, as House’s “Grinnin’ in Your Face” plays.

It all feels very personal; whatever you might already know -- and many fans will know a great deal -- the filter of a different prism still has the power to take you by surprise. And though it meanders at times between their back stories, it is best when it turns intimate. The Edge working in his studio on a wind-swept beach that looks as mournful as his music sometimes sounds. White so lost in a rangy riff that his fingers start to bleed. Page suddenly playing a mean air guitar, loose limbs following a silent beat.

And, of course, there is the music. In nearly every moment, an incredibly rich mix of their music, groundbreaking, defining, which alone would almost be enough. That “It Might Get Loud” comes with a righteous story too is a lovely bonus.

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betsy.sharkey@latimes.com

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‘It Might

Get Loud’

MPAA rating: PG for mild thematic elements, brief language and smoking

Running time: 1 hour, 37 minutes

Playing: In selected theaters