Sometimes it seems unfair that young rock artists, whose sounds and words are still evolving within the tempest of adolescent experience and professional inexperience, should have to bear intense, critical scrutiny. For 20-year-old Roddy Frame, leader of Scotland's Aztec Camera, the heavy expectations awaiting "Knife" (Sire 1-25183) are the unavoidable legacy of the group's auspicious 1983 debut, "High Land, Hard Rain." For 21-year-old Julian Lennon, the anticipation greeting his debut album, "Valotte" (Atlantic 80184-1), is no more than the burden of lineage. His dad was John.

The acclaim accorded Aztec Camera's first album was as much due to the group's innovative sound as to Frame's precocious lyrical skills and bright melodicism. With its textured array of acoustic guitars picking out jazz, country and flamenco-like patterns and its snappy rhythms, "High Land, Hard Rain" was nothing if not honestly innovative pop music. Now, with Mark Knopfler called in to produce, the band has simply lost more than it has gained. "Knife" reveals a sleeker, more refined rock sound with Frame's voice and words moved up front and the instrumentation pruned and subdued. As a result, the invigorating and eclectic musical panache of their debut is gone.

The one thing Knopfler hasn't sacrificed is the length of the eight original songs here; some of them run on past any musical purpose. "All I Need Is Everything" opens with a surging guitar figure and adds a delightful calypso rhythm before Frame's warm baritone offers with optimism, "These days are as bright as the days I have seen in the wildest of dreams."

But the fetching, sunshine quality of Frame's song dissipates as it meanders into the kind of smooth, cinematic sound Knopfler patented with his band, Dire Straits. In fact, all nine minutes of the title cut are little more than a drifting panorama of floating keyboards and guitars, a sound track in search of a plot.

Fortunately, Frame has not lost his melodic knack or poetic feel for the bittersweet traumas of youth. With a lovely introduction of Spanish guitar, "Backwards and Forwards" is a touching portrait of the confusion underlying the so-called golden years of adolescence. Likewise, the pure pop propulsion of "Still on Fire" and the jazzy "Just Like the USA" are full of Frame's daring, if sometimes overwrought lyricism. But as with one of his admirers, Elvis Costello, the emotional integrity underlying the tricky wordplay is Frame's saving grace.

In short, there's nothing wrong with Frame's songs; he is the talent everyone thinks he is. However, by sacrificing the bristling instrumental verve of its debut, by making use of a studio perfection in tone, color and mix, Aztec Camera has at least temporarily moved a step away from its creative iconoclasm toward a more ordinary professionalism.

It's hard to know exactly where Julian Lennon's talents might lie. With no real experience, he has been ushered into the rock arena with an expensive entourage of professional assistants perhaps to help cushion his fall. The most striking thing about his debut album, "Valotte," is that his thin, reedy tenor does eerily recall John Lennon, as do his vocal mannerisms. While most of the songs here are cast in the haunting, mid-tempo rock style John Lennon favored on his later albums, they too often are little more than dreary confessionals.

The titles -- "Well I Don't Know," "Lonely" or "Let Me Be" -- suggest the exhausted feel of these listless songs. Only a few numbers have any energy or melodic verve. While "Say You're Wrong" is an engaging and perky pop song, it is subverted by the ludicrous horn charts added by producer Phil Ramone. You have to wonder why a nascent rocker like Lennon would want the reliably bland Muscle Shoals rhythm section, much less sophisticated guest soloists like Michael Brecker, Toots Thielemans and Martin Briley.

In many respects, this whole project seems designed not just to hide Lennon's musical insecurities, but to make sure he doesn't get a chance to learn to make anything distinctive from his strengths and weaknesses. The tipoff is in his press bio, which acknowledges that early in his career "he was advised to prepare for a career in music, rather than jumping into live appearances and instant singles." When he does take this sleepy crop of self-pitying ballads on the road, he'll learn quick.