Heavy metal has never been particularly fashionable music. Rather than appealing to the listener's higher instincts, heavy metal goes for the gut, emphasizing physical impact in its sound, glandular reaction in its lyrics. Metal can be crude, true, but it can also amount to some of the most intensely effective rock on the market, if that aural assault is married to an equally straightforward melodic sensibility.

Take Ratt, for example. In its early days, this California quintet boasted the musical brawn of a sonic Schwarzenegger, but its debut EP did little more than tie that energy to a handful of sturdy riffs. By contrast, "Invasion of Your Privacy" (Atlantic 81257-1), its second album, finds the band sounding leaner, but no less mean, as Ratt channels its aggression into a genuinely winning set of pop songs.

Of course, Ratt's approach to pop hardly amounts to what you'd expect from, say, Wham! The album starts off with a snarl, as the band's hyperamplified guitars stutter the introduction to "You're in Love," and proceeds apace. There's plenty of screaming guitar here, thanks to Warren De Martini's ferociously inventive solos, and the basic pulse is pounded home with ear-shattering enthusiasm. But "Invasion of Your Privacy" never pushes power for its own sake, and despite the allure of the overall sonic assault, it's the songs themselves that ultimately hold your attention.

Part of that, needless to say, is the writing, which is brutally efficient in its use of melodic ideas. "Between the Eyes," "Closer to My Heart," and "Lay It Down" are classic examples of how to focus a song on its hook; and each song drives home its chorus with admirable zeal.

But equal credit belongs to producer Beau Hill, who has lent a solid crunch to the guitars and powerful punch to the drums, while still managing to favor Stephen Pearcy's singing in the mix. That balance between vocal and instrumental power is the real key to Ratt's sound, for to maintain maximum impact throughout the album, the band has learned to pare each song to its essential elements. As such, "Invasion of Your Privacy" doesn't let up for an instant, making it power-pop in the most literal sense.

Power is something Mo tley Cru e's albums never had much of, and that was odd, given the band's bad-boy image. The Cru e, after all, presented itself as being nastier than Kiss, louder than Judas Priest and raunchier than Van Halen. Yet the band's first two albums sounded like heavy bubble gum, backing lackluster, derivative songs with pantywaist power chords. Listening to the band, one finds it hard to imagine what all the fuss was about.

"Theatre of Pain" (Elektra 60418-1-E), the band's third album, musters a little more muscle than its predecessors, but still ends up sounding like something of a confidence job. Sure, the band looks tough from the lyric sheet -- the titles here include "Fighting for Your Rights," "Raise Your Hands to Rock" and "Louder Than Hell" -- but what the band delivers is considerably less ferocious.

The single, a remake of Brownsville Station's "Smokin' in the Boy's Room," offers little that the original didn't already have, and the band's own tunes simply regurgitate what Mo tley Cru e has absorbed from Black Sabbath ("Louder Than Hell"), Deep Purple ("City Boy Blues") and Judas Priest ("Use It or Lose It"). "Home Sweet Home" shows some originality in seeming to match Aerosmith with John Denver. But it's hard to imagine the point of such a fusion.

Mostly the music seems hollow. Because the band members themselves appear incapable of supporting their sound in the studio, the credits are littered with thank-yous to the musicians who fleshed out the songs. As was the case with Quiet Riot, this is a band that desperately needs stand-ins. Which is fairly ironic, in light of its stand-on-your-own brand of rebellion. In the end, Mo tley Cru e's alleged menace is comic in its ambition.

Night Ranger has no menace, nor anything else resembling an image. This band is a wonder of technique, having extracted the essential mannerisms of most of the past decade's popular heavy-rock acts and ground them into a highly marketable paste. "Seven Wishes" (MCA-5593) is as faceless as chart-topping rock gets. Yet thanks to the band's ability to plant hooks in the most banal of material imaginable, this album is catchy in spite of itself.

To an extent, Night Ranger is a throwback to the hard-pop sound of the late '70s, when the ability to reduce heavy metal's crunch to Top 40 dimensions was the key to commercial success. Night Ranger certainly understands how to make its ideas bigger than they really are; from the title song through "Sentimental Street" and "Interstate Love Affair," the band blows up every riff to mock-epic proportions through carefully crafted arrangements.

Where Night Ranger falls short, though, is in its content. It's understandable that the material should be on the fluffy side. But what ultimately sours "Seven Wishes" is the misogyny of its lyrics, for from the blatant objectification of "I Need a Woman" to the date-rape mind-set detailed in "This Boy Needs to Rock," Night Ranger defines itself as sleaze of the worst kind.