‘Love, Janis’

Watching footage of Janis Joplin at the 1967 Monterey International Pop Festival, you can see why Mama Cass, sitting in the crowd, keeps shaking her head. There’s Janis, decked out in full gold lamé and tiny mules, shaking and snarling her way through “Ball and Chain� as if she’s tearing apart a small animal.

The performance is part Muddy Waters, part Bridget Jones, a wild collision of mojo and nerd. Writing about it for Rolling Stone, Rosanne Cash described Joplin as some kind of nuclear being bearing down on the crowd. She had an unshakable commitment to her own truth, no matter how destructive, weird or bad.

The beauty and the power of Joplin as a singer came from her complete lack of fear. She held nothing back. By contrast, “Love, Janis,� playing this weekend at the Wilshire Theatre, takes a more mellow spin through the last years of Joplin’s short life, from her early breakout performances in San Francisco to her final days in Los Angeles in October 1970.

Backed by a high-energy band, Joplin the singer is portrayed by an exuberant Mary Bridget Davies (alternating with Andra Mitrovich), her spoken self by Marisa Ryan. The notion of dual Joplins makes dramatic sense: How better to mine the gap between the rock goddess who made love to 20,000 people with a song and the awkward college student at the University of Texas who was once nominated for ‘ugliest man on campus�?

But this easygoing concert show -- conceived, adapted and directed by Randal Myler from a biography by Laura Joplin, the singer’s sister -- keeps its distance from the performer’s depths. On the one hand, it’s refreshing to take a break from rock-star clichés, but this pioneer geek hippie chick lived pretty large, and Myler’s tribute show, despite a full-throttle effort from Davies, contains its subject rather than opening her up. No mention is made of her numerous affairs with women, and her struggle with substance abuse is barely touched on. This is definitely G-rated Janis.

“Love, Janis� is also a little time capsule of Haight-Ashbury, land of velvet bell bottoms, feather boas and love beads. Colorful psychedelia appears on upstage screens during concert scenes, and the band plays as if it’s tripping out with thousands of acid-dropping fans. The only spoken text is taken from interviews Joplin gave and letters she wrote to her family.

Of course, the press and our parents are the last people to whom we tell the truth, so Myler’s portrait feels as tidy as an annual family holiday card. There are a few memorable lines: Janis skeptically notes she’s not sold on becoming a poor man’s Cher and later crows over the cash she gets from the maker of Southern Comfort, her favorite refreshment (“the most money I ever made from passing out�). But you can’t help imagining the tougher, more textured show that might have been.

As Speaking Janis, Ryan presents us with a wry, nervous young woman still trying to settle into her own skin, but the play doesn’t offer her much in the way of range. Still, if the emotional heft of “Love, Janis� gets pushed onto the music, no problem: Davies is gonna carry that weight. She happily puts her big, bluesy voice straight down into the songs, capturing a hunk of Joplin’s signature rasp and screech. The evening is buoyed by her generous presence: She gives “Summertime� a sweet throb, “Ball and Chain� a real kick in the gut. She may not take you to extremes the way Bette Midler did in “The Rose,� but Davies affirms the soul in the center of the Joplin hurricane.

The band, led by Eric Massimino, pumps plenty of energy into the atmosphere. Yet even though they go out on a sternum-vibrating encore that leaves you nostalgically recalling the first time you went partially deaf after a rock concert, these musicians -- like the whole show -- leave you wanting more Janis.