Seven years ago, when rock singer Matthew Sweet first headlined Taste of Chicago, Grant Park was so packed you'd have thought Michael Jordan had stuck around for an extended championship party. Although surprisingly cold winds and an ominous fog over Loop skyscrapers probably had something to do with it, the turkey-leg-gnawing Petrillo Bandshell crowd was about half-full Thursday when Sweet took the stage.

Like his opening act and longtime friends, the Jayhawks, Sweet's star power has slowly diminished since then. His albums haven't had the same perfect pop snap as 1991's "Girlfriend," and mainstream tastes have moved on from loud guitars and passionate shrieking. Neither Omaha-born Sweet nor Minneapolis' Jayhawks seemed to mind: Their songs may be newer, but they've barely changed their live sound.

Sweet's modus operandi is basic rock 'n' roll, cranked just loud enough that you can't hear all the words. As usual, he had a lead guitarist — Pete Phillips, dressed in white and looking like the Leaning Tower of Pisa in the corner — to fling dissonant solos against the catchy melodies. And as usual, Sweet stood at stage center, flailing power chords on his rhythm guitar and screaming his high pitch above the din.

Opening with songs from last year's uneven "In Reverse," including "Millennium Blues," complete with trumpet, Sweet struggled temporarily to hold the crowd's attention. Then he made reference to the 1993 show — which the Jayhawks also opened — and dug into his catalog, reeling off the religious-skepticism anthem "Divine Intervention," a three-guitar "Time Capsule" and the punked-up Beach Boys homage "Come to California."

As a songwriter, Sweet alternates between pretty love songs and hateful rants. In concert, he renders them almost indistinguishable, applying the same stomping rock formula to "I've Been Waiting" ("didn't think I'd find you perfect in so many ways") and "Ugly Truth Rock" ("the ugly truth makes every one of us a liar"). He unites love and hate in one of his best songs, "Sick of Myself," which the band filled with dramatic false endings. For the encore, pushing curfew, they rushed through "Girlfriend."

After 16 years as a country-rock band, the Jayhawks have meticulously developed their best choruses into hymns. The quintet's best album remains 1992's "Hollywood Town Hall," and at Grant Park their beyond-the-Byrds harmonies jelled perfectly on the "each time when I go to bed I pray" line from "Take Me With You (When You Go)." Relatively new keyboardist Jen Gunderman's organ added to the swirling psychedelic feel.

The Jayhawks emphasized their latest album, "Smile," whose happy title track is sort of the glass-half-full version of R.E.M.'s melancholy "Everybody Hurts." ("Chin up, chin up!" goes the chorus.) By contrast, the attack-song "Somewhere in Ohio" opened with a hip-hop drumbeat and maintained a killer funk groove.

Curly haired singer Gary Louris, wearing a long white shirt, white slacks and hipster shades despite the impending clouds, doesn't have quite Sweet's frontman presence.

But for what the Jayhawks lack in visual charisma, they more than compensate with richness and soul.