ROBERT PALMER - "Secrets" (Island ILTS 9 9544).

There's no clear reason Robert Palmer should not be at the top of rock's pantheon. If you were to list the qualities generally associated with superstardom, Palmer would probably rate on most of them. His songs are melodically strong and aviod formulas. He has a superb sense of rhythm that he uses for maximum effect. His stage show is crisp and exciting, and Palmer himself is movie-star handsome.

So here he is, having just released his fifth solo album, "Secrets," and he's still trying to establish a mass following. Not that Palmer hasn't done well. His previous albums and concert apperances have been met with critical and popular acceptance, but he's just never scaled the heights that people - including his record company - thought were his for the taking.

"Secrets" is a slight departure from the usual Palmer fare and might contain the elments necessary to put him in front of a wider audience. For one thing, there are several songs that could be hit singles, something Palmer has never been able to achieve nationally. Also, on the whole, "Secrets" is a much more overt attempt at straight rock and roll. The immediate effect is that, though some of the tunes are more tedious than is usual with Palmer, the record as a whole might be more palatable to an audience that seems to be getting back to basics.

Plamer is a stylish as much as a rock singer, and his ability to bend phrases and play with tempos has always been part of his strength. He doesn't abandon these traits on "Secrets," but side two especially plays it pretty straight. However, this sublimation of style for increased power does allow Palmer's band to function much more cohesively than on some previous works.

"Secrets" was recorded near Palmer's home in Nassau, and the band is the same one that accompanied him on his last tour. The resulting ease and familiarity between Palmer and his band allows for tighter vocal harmonies and more intricate musical undercurrents.

Keyboardists Jack Waldmand and Steve Robbins constantly slip in tasteful synthesizer fills or pulsing organ runs that accentuate Palmer's rhythmic base. Bassist Pierre Brock is everywhere, keeping up a steady foundation with drummer Dony Wynn. Guitarist Kenny Mazur is used more for depth than leads, but he's quite capable when called upon and perfect in his role as the rhythm section's glue.

Still, "Secrets" is structured in a way that leaves one wondering just what audience Palmer is after. Side one seems to rely mainly on his vocal style and some throbbing cross-rhythms, much in the manner of his earlier works. Side two is much more rock'n'roll-oriented and Palmer's vocals are much more direct.

The album opens with a current single, "Bad Case of Loving You (Doctor Doctor)." This is a rocker, but has all the Palmer vocal tricks that make him distinctive: unexpected pauses, a slight variation on some of the same riffs and a general tendency to rock without sounding cliched. What's most important commercially is that "Bad Case of Loving You" should sound terrific as a summer single and could get the album off to a fast start. (Itoncially, many people felt that "You're Gonna Get What's Coming" - a similar rocker on Palmer's previous release, "Double Fun" - should have been a single last summer. But it was never released, and lacking a hit, the album did not do as well as Island Records had hoped.)

In the past Palmer's most heavily played tunes werre lush, eerie ballards lide "Give Me an Inch" and "You Overwhelm Me"; such songs are conspicuously absent from "Secrets." With the possible exception of Todd Rundgren's "Can We Still Be Friends?," the album is devoid of heavily layered slower numbers. "Mean Old World" is ballad-like but more simply stated, and nothing else even approaches the textures of "You Overhelm Me."

Yet, Palmer's passion for reggae is still in evidence and he - more than any non-Jamaican - manages to make it a personal statement. "Too Good to Be True" has a slinky, hypnotic rhythm that makes great dance music, and "In Walks Love Again" is lighter on the reggae, but still projects a Caribbean flavor.

More conventional rockers dominate the rest of the album. "Love Stop" and "Remember" keep some individual flair, but "Jealous," "Under Suspicion" (distinctive for its more menacing vocal approach), "Woman You're Wonderful" and "What's It Take" carry through on steady tempos.

Palmer can deliver most anything with elan, and on "Secrets" he does. His lyrics deal almost solely with the relationship between men and women, so he certainly won't lose anyone to complex subject matter.

All Palmer seems to need to finally reach the pinnacle are some well-chosen singles. "Secrets" has the potential - but then, Robert Palmer knows all about potential. CAPTION: Picture, ROBERT PALMER: TRY. TRY AGAIN.