Morissette, Amos: Mixed Doubles in Irvine

Tori Amos and Alanis Morissette, two of this decade’s foremost rock divas, finished a joint excursion dubbed the “5 1/2 Weeks Tour” over the weekend at Irvine Meadows. Their separate sets, with no collaborative moments, might best be understood in terms of a song title by their peer, Sarah McLachlan: “Building a Mystery.”

Morissette, whose painfully plain-spoken lyrics often read like unsent letters or self-help exercises recommended by a psychotherapist, tried hard on Saturday, the first show of a scheduled two-nighter, to build some mystery into her baldly declarative songs. Material from her album “Supposed Former Infatuation Junkie”frequently resorted to that instant aural signifier of mysteriousness, portent-laden Middle Eastern stylings a la Led Zeppelin’s “Kashmir.”

Morissette’s young band played those well, but a chunk of her newer stuff suffers from melodic blandness that her highly stylized, trumpeting, breath-heaving voice couldn’t rescue. Her 70-minute set flowered when she dropped any hint of mysteriousness and cast herself as the guileless, life-affirming young woman of the hits “Thank U,” “You Learn” and “Hand in My Pocket.”

Decked out in bright crimson eye makeup, stringy brown hair long enough to sweep the floor when she bent over at the waist, and neo-Deadhead regalia that included a T-shirt imprinted with a nude female torso, Morissette was a fetching naif figure whose winning, fresh smile helped beam across these songs of possibility. They were the credos of a young woman committed to soaking up as much experience as she can, and willing, even eager, to take some hard knocks to get it.

Amos doesn’t have to build mysteries--she is one. This is one of the most enigmatic and sometimes simply baffling songwriters successful enough to line her walls with awards for platinum albums (her sales, ranging from 661,000 to 1.6 million, according to the SoundScan monitoring service, are no match for Morissette’s 13.4-million seller, “Jagged Little Pill” and the 2.3 million sales for “Infatuation Junkie”).

Playing an opening set that was slightly longer than Morissette’s, Amos oscillated like a subatomic particle whose exact nature can’t be pinned down. She was the yearning balladeer of “1000 Oceans,” a song from her new album, “To Venus and Back,” that’s lovely and simple and still and heart-pouring enough for Emmylou Harris to cover. But she also was the singer whose stuff can be downright inscrutable, sealed off in her own coded world of symbols and visions. It didn’t help that at times Amos’ voice was obscured by the layered sound of her three-man band and her grand piano and synthesizer.

But on balance, the mystery was alluring, as even the thornier, less pithy songs held interest as they swung between dense, storming band passages and ones in which Amos’ pure voice took flight in the soaring soprano art-song curlicues she got from Kate Bush.

Amos, clad in tight jeans and a white blouse whose dangling strings called to mind a straitjacket, made an arresting madwoman. Sometimes she wore a baleful, frightened gaze. At other moments, she smiled with the weird serenity of a saint being burned as a witch, knowing that her tormentors will have to answer for it.

Sex and religion rub up against each other regularly in Amos’ songs. At the start, she rubbed up against her piano like an exotic dancer against a strip club’s stage pole, then began singing “God,” which suggests that he might order things on Earth better given “a woman to look after you.”

Sometimes that stormy-then-dulcet pattern grew diffuse. But the set took on a sharp, brilliant focus with two songs that Amos, who for years toured as a solo-acoustic act and still is most distinctive in that mode, played without her band. Her version of Nirvana’s “Smells Like Teen Spirit” (originally released in 1992, when the hit was fresh and Kurt Cobain still lived) deployed the rasp of a used-up female barfly and a delicate cry of isolation. Very scary. Then came the lovely “1000 Oceans,” which comes across as a fine, modern successor to the traditional folk ballad “The Water Is Wide.”

The guitar-bass-drums backup clicked for Amos near the end with “Waitress” and “These Precious Things.” Both built to surging, intense climaxes that carried her keening voice on dark sonic waves.

Perhaps, watching from the wings on this tour, Morissette has been able to absorb the best of Amos--the part in which meanings might be a little elusive, but one still gets the gist (that side comes out best on Amos’ 1991 release, “Little Earthquakes” and “From the Choirgirl Hotel,’ 1998). The way for Alanis to build that mystery is to punch some holes in the prosaic (if true-ringing) litanies full of bald, unadorned declaration that she favors.