IF THERE'S a special circle of hell reserved for tuneful pop-rock bands, it's probably the trauma of opening a concert for heavy-metal acts such as Pat Travers and Ritchie Blackmore.

After all, nothing makes a 9-to-5 job look quite so appealing as the sight of thousands of power-chord-hungry fans expressing distaste for your music. No wonder Washington's 4 Out of 5 Doctors' recent tours with Travers and Blackmore have altered its musical perspective somewhat.

Or maybe it's simply the departure of producer Alan Winstanley (an Englishman whose credits include albums by Rachel Sweet and Madness) and the arrival of Jeff Glixman (Kansas and Magnum) that has made the Doctors' sophomore album "2nd Opinion" (Nemperor ARZ 37700) so much more rigid than their first.

Whatever the reason, it's clear that the Doctors are taking themselves a lot more seriously these days. Where the band's widely acclaimed debut album intelligently and often amusingly wed disparate rock influences--the Beatles, Steely Dan, the Raspberries, among others--to clever, insinuating melodies, their second album takes a more calculated approach.

The album opens with "Good Pretender," a song that aspires to nothing so much as the mediocrity and commercial success of FM stalwarts such as Foreigner, REO Speedwagon and Styx. Which isn't to say that the Doctors' true strengths--bassist Cal Everett's galvanizing lead vocals and the band's sculptured harmonies--are any less polished than before. It's just that they are incidental on this tune and the two that follow--the forgettable "Dawn Patrol" and "Anna With Antennae"--all of which place the emphasis squarely on sweeping guitar tapestries and jackhammer percussion.

"Breaking Rocks," a logical choice as a single, if for no other reason than it exploits a simple, emphatic refrain, isn't much better. In fact, of all the songs on side one, only the Raspberry-flavored "Never Say Die" comes close to suggesting the buoyant pulse of the Doctors' debut album. The band sounds oddly imitative and anonymous on the songs that precede it.

Fortunately, "2nd Opinion" has a second side. If the opening numbers are aimed at securing the Doctors airplay--can there be another explanation for such a dramatic about-face?--then the flip side is an overdue reminder of the Doctors' winning charm and potential.

The band's sound isn't quite as diffuse as it once was. Glixman has brought Everett's bass into sharper focus and now a denser, bottom-heavy drive propels the music. But on songs such as "Waiting for Roxanne," "Call Me at Home" and the album's best, "Heart on a Chain," the Doctors' synthesis of New Wave rhythms and earlier rock elements still seizes your attention.

The bright, invigorating "Roxanne" is a perfect example, combining razor-sharp harmonies, pulsating keyboards, quirky rhythms and a verse that recalls, of all things, Bobby Darin's "Dream Lover." "Heart on a Chain" leans heavily on word play and the backbeat, while the staggered voicings on "Call Me at Home" are crisp and colorful.

So in a sense, "2nd Opinion" is both the best and the worst of 4 out of 5 Doctors. Always derivative--and delightfully so--the band has now become imitative as well. It will be interesting to see which strategy brings them a larger audience as time passes. In the meantime, they will perform at the Bayou on Tuesday.

By comparison, there's nothing the least bit ambiguous about the direction Washingtonian Terry Scott is taking on his debut album, "Terry Scott" (Elektra 60014). A black musician, Scott has his work cut out for him trying to crack the white-dominated rock play lists, and if he fails it won't be for want of talent. Scott has plenty of that; he'll display it Thursday and on April 18 at the Outside Inn in Rockville.

In addition to being a gifted guitarist and keyboard player, Scott is a confident rock singer whose voice isn't easily categorized. On "Over and Over," one of the album's typically lavish yet solid rock productions, Scott sounds a bit like Stevie Wonder might if he aimed for high-powered rock. Later, on the less strenuous "Teenage Runaway," Scott's delivery suggests Elton John's phrasing.

Whether these influences are real or imagined matters little. Scott immediately proves himself a more than capable rocker on this album. If his songs aren't always particularly memorable, at least they're never boring, and you can't help but admire their detailed construction.

The keyboard and guitar textures Scott creates on both "Over and Over" and "She Don't Belong to Me" are quite exceptional, and the acoustic setting for "Teenage Runaway" is surprisingly sophisticated for a debut effort. Scott's lyrics, which range from the sensual ("She Don't Belong to Me") to the inspirational ("Believe in a Dream") to the ponderous ("March to the Execution"), are also, by and large, several cuts above what's passing for par currently. He is clearly a talent that bears watching.