Attending Thursday's Post-Gazette Pavilion concert was rough all the way around.

For openers, rain -- and the threat of more --likely kept the crowd down, with literally no one seated on the lawn.

Worse, the overall sound went south.

It was that latter item that marred the show from Chicago, formed just over 40 years ago as the first rock band with an integrated brass section, as it performed a set that reflected that history. The group managed to squeeze years of favorite songs -- many of them truncated, nevertheless -- in just a little under two hours.

As befits a band that's been around that long, it played pretty well. Or at least I think it did because at points the horns were literally inaudible, the vocals a little weak and a couple of numbers were just too loud overall. In addition, the volume on Robert Lamm's keyboard on the introduction to "Saturday in the Park" just wasn't there during the first few chords.

Although Chicago in the 1980s became known for its ballads, the audience actually got cranked most to its harder-rocking, up-tempo material, especially "Alive Again," the back end of "Feelin' Stronger Every Day" and the closing "Get Away." I especially appreciated the funky "90 Degrees and Freezing," the best song from last year's "XXX."

The strongest part of the show was the medley from "Chicago 19" that featured Bill Champlin. The organist and vocal replacement for the late Terry Kath also wields a pretty mean guitar, especially on "You're Not Alone," during which he traded off with guitarist Keith Howland.

And there was a surprise, too: The Brazilian-influenced "You Are on My Mind," featuring trombonist Jimmy Pankow on lead vocal.

America, the band of military brats that started as an acoustic trio, opened the show with a set a bit punchier than its recordings but did not depart from them musically -- only the closing "Sandman" was stretched beyond its original arrangement. Thankfully, that portion was sonically more stable.

Like Chicago, America, today including Dewey Bunnell and Gerry Beckley, has a considerable list of hit songs. Two selections on the Thursday bill were the more obscure "Don't Cross the River" and "Riverside." Bassist Rich Campbell supplied the extra voice that replaced the departed Dan Peek.

The highlight of that segment was the encore of the lyrically surreal "A Horse With No Name," with Beckley playing a jangly Rickenbacker guitar, befitting America's folk roots.

Chicago later brought back Bunnell and Beckley to do "Wishing You Were Here," "Beginnings" and "You Can Do Magic," with Lamm singing the bridge.