"Hi Infidelity," R.E.O. Speedwagon's last record, was the second-largest-selling album in America for CBS Records. That means it out-sold Billy Joel's "The Stranger," Simon and Garfunkel's "Bridge Over Troubled Water," Pink Floyd's "The Wall" and Michael Jackson's "Off the Wall." A hard act to follow, this.

Or is it? In many ways, the success of "Hi Infidelity" reflected the times -- tight, conservative radio playlists hungry for palatable rock -- more than any changes in the band's sound or appeal. Through teen audiences thick substantive and thin, R.E.O.'s music has remained much the same over the past dozen years. While the hit single "Keep on Loving You" and its followers may have put the band in the black for good, it didn't alter R.E.O.'s course one whit: It continued happily down the middle of the road.

The band's new album, "Good Trouble," isn't likely to find current market conditions quite so hospitable as its predecessor did. But its success is guaranteed because lead singer and chief songwriter Kevin Cronin knows his audience well. The mix of acoustic and electric guitars, interrupted by an occasional piano or organ break and those consistently appealing choruses, are tailor-made for airplay. "Keep the Fires Burning" has already reached the top 10 and there seem to be plenty of other contenders waiting in line.

Cronin can claim the credit. He can wax romantic on the unabashed "Sweet Time" or, with the help of Gary Richrath's guitar sweeps, affect a quasi-heavy-metal stance on "Stillness of the Night." But his real strength lies somewhere between those styles: It's a combination of pop accessibility and power-chord punch that defines REO's appeal. Nowhere is that more apparent than in the songs Cronin sings.

Even so, the band's greatest liability, as always, lies in its lyrics. The love songs are invariably banal or cliched -- sometimes both -- and the band's occasional attempts at expressing something more personal and original hardly fare better. (To wit: bassist Bruce Hall thanks the band's new-found fandom with the coyly sentimental "Let's Beebop.")

Then again, who can argue with Richrath's view of the group: "We make albums for kids -- 13-year-old kids, 25-year-old kids, 40-year-old kids." "Good Trouble" is just that -- kidstuff with no apologies.

While R.E.O. Speedwagon hasn't changed, Cheap Trick has -- and for the worse. Increasingly, Rick Nielsen's songs have steered the group from its once campy and cunning tongue-in-cheekery to the ponderous wail of heavy metal.

Of course, megawattage is no stranger to Cheap Trick; it has always been the source of Nielsen's brawny guitar lines and it worked well behind Robin Zander's keening vocals. Unfortunately, the band's latest album, "One to One," doesn't have much else to offer.

Doubtless, some of these songs will work better in concert amid the band's loony stage antics. There is one infectiously quirky tune called "Saturday at Midnight," a throwback to the band's new-wavish days, and the oddly familiar "If You Want My Love," with a bridge borrowed straight from George Harrison's "While My Guitar Gently Weeps." Beatle-esque harmonies and fades sweep through these, the best tracks. But for the most part, "One on One" is a strangely humorless and calculated album. Maybe this is Cheap Trick's aural assault on the heavy-metal kingpins; if so, they're well-prepared with the requisite firepower and lug-headed tunes.

ON RECORD, ON STAGE

THE ALBUMS

R.E.O. SPEEDWAGON: Good Trouble (Epic FE 38100).

CHEAP TRICK: One on One (Epic FE 38021).

THE CONCERTS

R.E.O. SPEEDWAGON: September 1 at 8 at the Capital Centre.

CHEAP TRICK: August 30 at 7:30 at the Merriweather Post Pavilion.