Though it doesn’t seem that Chicago will ever shake up their setlists or rediscover their original mission, at least they can still sneak just a little Varese in with the hits.

Cover art for Chicago’s latest album — “Now.”

By Brett Milano

Chicago was the first big concert I ever saw, at Madison Square Garden in 1973 — at which time, their new chartbound single was “Feelin’ Stronger Every Day” and their opening act was a newcomer named Bruce Springsteen (whose songs, I thought that night, had too many damn words). This was long before the slick ballads, when Chicago was still a young and idealistic band, on a mission to bring some progressive music to the Top 40 (Album #5 even opened with a song called “A Hit By Varese”). Those heady days pretty much ended with the accidental death of guitarist Terry Kath in 1979. Still, I’ve managed to check in with the band every few years, just to see if any of their original spirit might resurface. A hard habit to break, you might say.

This year the band quietly released a new album, Now, which finally brings some of their old sound back. For the first time since the ‘80s, they worked on their own without commercial producers or song doctors, putting singer/keyboardist Robert Lamm (who was effectively benched during the commercial years) back at the helm. Though not quite up to their first and best albums, it’s a step in that direction, the first in decades to evince any jazz influence. At the Pavilion they played the title track, a sophisticated samba right up the Stevie Wonder/Steely Dan alley.

But there’s the rub: Promoting their best album in decades, Chicago ventured only one song from it. Otherwise, they did their job and stuck with the proven crowdpleasers. Four of seven original members are still officially in the lineup —Lamm and the horn section of James Pankow (trombone), Walt Parazaider (sax) and Lee Loughnane (trumpet) — but the horn players have regular subs and don’t make every gig; Parazaider was absent this week. Most of the leads went to singer/bassist Jason Scheff, who’s been singing Peter Cetera’s high parts for so long (Scheff replaced him in 1986) that it gets hard to tell the two apart.

Chicago (circa 2014) on tour

It’s telling, however, that they avoided the ‘80s almost entirely, doing only two songs (“You’re the Inspiration” and “Hard to Say I’m Sorry”) from the endless ballad era — in contrast, there were four from 1969’s debut album Chicago Transit Authority alone. And they seemed determined to stretch out whenever the airtight arrangements would let them: Guitarist Keith Howland has absorbed some of Kath’s unhinged way with a wah-wah. On “Just You & Me” standin saxophonist Ray Hermann blew a soprano solo that was skronkier than anything Parazaider ever ventured; and during “I’m a Man” (the Spencer Davis Group tune that Chicago have covered since the beginning) they broke into a chaotic percussion jam. Though it doesn’t seem that Chicago will ever shake up their setlists or rediscover their original mission, at least they can still sneak just a little Varese in with the hits.

Coheadlining this tour is REO Speedwagon, who remain the embodiment of a nice-guy Midwestern bar band — they got lucky with one album, Hi Infidelity, which even progressive stations like WBCN were playing to death in 1980. Not surprisingly they played most of it this week, and joined Chicago for a half-hour finale of each band’s barnstormer numbers. With both bands onstage, all the parts were doubled on Chicago’s “25 or 6 to 4,” which I guess makes it more like “50 or 12 to 8.”

Brett Milano has been covering music in Boston for decades, and is the author of Vinyl Junkies: Adventures in Record Collecting (St. Martins, 2001) and The Sound of Our Town: A History of Boston Rock & Roll (Commonwealth Editions, 2007). He recently returned from New Orleans where he was editor of the music and culture magazine OffBeat.