Jeff Beck and George Benson are two guitarists who will probably never sit down together for a midnight jam session. Their styles have always been at odds: Benson the consummate light-jazz doodler, insistently melodic; Beck the braggadocio blues screamer, intent on ushering in the apocalypse with a note that could move a subway train. George Benson might have watched with horror the scene in "Blowup" where Yardbird Jeff Beck smashed his screeching instrument into a Marshall amp. And that was more than 10 years ago. Now, despite Benson's foray into pop and Beck's into jazz, they are, in spirit at least, even farther apart.

Beck, who will make a rare Washington appearance Oct. 14 at Constitution Hall, left the blues format some years ago because his strengths had been threatening to drag his music into self-parody. His band had degenerated into an excuse for Beck to unleash his Les Paul. Considering the talent of other members (Rod Stewart, Nicky Hopkins), this was not an economic situation. Eventually Beck linked with keyboardist Jan Hammer, and a new sound emerged -- a sort of jazz-rock fusion which was premiered succussfully on "Blow By Blow." Its latest incarnation is "There And Back" (Epic FE 35684). It still works.

The secret lies in having a sound that can accommodate, but not absorb, Beck's Wagnerian guitar antics. "There and Back" has all the trappings of fusion music -- soaring synthesizers, a complex (and wholly admirable) drumming performance, no singing -- but Beck's playing is still unreconstituted rock-blues. Away from a strict blues structure, though, Beck is free to roam here, there, back and anywhere. He changes tempo, modulates volume, and bats his notes into the lower reaches of outer space. At no time does he allow the melodies (yes, there are melodies here, however fleeting) to transform his fireworks performance into a plain old song.

And when his co-performers threaten to get to jazzy, Beck has them settle down into rather pedestrian riff, onto which he sets down layers of guitar wizardry. It's a steadily exhilarating trip. Best of all, "There and Back" shows how a heavy-metal blues guitarist can tamper with his genre, forgo lyrics and traditional lead patterns, and find true happiness. Not to mention big sales.

George Benson, who appears at the Merriweather Post Pavillion this Sunday, is another guitarist who is no stranger to the upper levels of the charts. This success is a relatively recent development in his long career. Formerly he was content to play cool jazz to a limited, devoted audience. "This Masquerade" changed all that -- he learned that his singing was as powerful a force as his playing. And so began a string of best sellers, each one bringing him a little closer to the middle of the musical road, further from the percieved purity of his beginnings. Early fans have all but concluded that Benson's cause is a lost one. Of course, their complaints are drowned out by the enthusiastic clamor of his many new fans.

On his latest, "Give Me The Night" (Warners HS 3435), Benson has a new collaborator, producer Quincy Jones. Jones is a man of orchestral talents and a producer of enough movie soundtracks to keep Home Box Office humming for weeks. Under his black-Muzak influence, Benson is more easy-listening than ever. At times, it sounds like he's doing a slimmed-down version of the Barry White show, complete with adoring female co-vocalist.

Oh, that charming guitar is still there. But when it solos, the clear, ringing notes have to compete with a mix that exphasizes drums and strings. And Benson's habit of scatsinging an accompaniment to his guitar leads is getting tired -- even though the scat-singing sometimes manages to hit more notes than the guitar does.

This is not to say that "Give Me The Night" is in any way sloppy or unorganized. To the contrary, the album is so impressive in its professionalism, sophistication and foot-tapping moodiness. Within its own somnambulant parameters, it even swings. Some of the tunes are catchy (though the lyrics are without exception hackneyed), and the title song, released as a single, already has America nodding in soporific approval.

But for this reviewer, the key moment of the album comes at the end of Benson's rendition of the jazz classic, "Moody's Motel." The singing over, Benson says, "James Moody you can come on in, man. You can blow now if you want to." This is usually a signal for some soul-blasting horn solo. But no musician appears. Nothing happens. And so it goes, 40 minutes of musical foreplay without a hint of climax.