Many of Ireland's greatest artists have found their inspiration in the transcendent breadth of Celtic mysticism. Their artistic opposites, in some ways, are American blues singers, who, from Robert Johnson to Ray Charles, have found their inspiration in the illuminating flash of the moment.

Incredibly enough, Van Morrison, the "Belfast Cowboy" (as Robbie Robertson dubbed him), has been able to fuse these elements. On his previous four albums, Morrison tilted the balance of his music heavily in the direction of Celtic mysticism, but on his new album, "A Sense of Wonder" (Mercury, 822 895-1 M-1), his music is again infused with a good dose of rhythm and blues, and is better for it. This time when he lets loose with his big, big voice, out come both the rasp of desire and the hum of awe, one following naturally out of the other.

Much like the great jazz saxophonists of the '60s, Morrison's leathery throat can leap through twisting improvisations to find the equivalent for his frustration, or it can spread into the lush overtones of contentment. Even when singing wordless vowels on the album's two instrumentals, his voice delivers a convincing monologue.

On "Tore Down a la Rimbaud," he sings of suffering through writer's block and waiting for the poetic Muse; he longs for not only Rimbaud but also the stimulation of gallery paintings and library books. Yet he approaches these refined subjects as if waiting for a woman at a Saturday night roadhouse; the punchy R & B is enlivened by horn riffs and echoing female vocals.

When he sings Ray Charles' "What Would I Do Without You?" he delivers lines like "I'm crazy about my baby" with the breathy reverence of a solemn hymn giving way to an improvised twist of the voice. He sings Mose Allison's "If You Only Knew" and William Blake's "Let the Slave Flash the Price of Experience" back to back, and the blues pianist's common-sense rap on the lessons of experience is not that different from the Romantic poet's visionary declarations on the topic.

Morrison is backed by his regular band of several years; John Allair's organ pumps up the Allison and Charles songs, while Chris Michie adds Knopfleresque riffs to the long, haunting title song.

The most imposing presence, though, is jazz legend Pee Wee Ellis, whose saxophone matches the excursions of Morrison's voice from the street-corner shouts to the Celtic twilight and back again, turning nearly every song into a duet between the voice and its shadow. The ambition and accomplishment of this album should give every attentive listener the "sense of wonder" the title promises.

Many vocalists have felt themselves called to Morrison's style of songwriting and singing; few have been chosen. One of the few has been Joan Armatrading, who performs at Constitution Hall on Wednesday. She, too, has an uncanny ability to penetrate the most common romantic encounters and discover something transcendent.

Yet her recording career has never matched Morrison's, simply because she has never won the control in the studio that he has. Her latest album, "Secret Secrets" (A&M, SP 5040), bears the same frustrated promise as her recent releases: inspired singing on excellent songs is often obscured by totally wrongheaded production.

This time the culprit is producer Mike Howlett, following in the footsteps of Steve Lillywhite, Val Garay and Richard Gottehrer. All four producers have trampled on the "sense of wonder" in Armatrading's vocals with jarringly inappropriate hard-rock guitar; all have sabotaged the stark economy of her songwriting with excessive synthesizers. At least half the songs on the new album, though, are so strong that they are not to be denied, even by someone as clumsy as Howlett. Armatrading's melodies are stronger than they've been in years and her chord changes more interesting than ever.

The first single, "Temptation," has a chorus hook so glorious and a vocal so demanding that it's irresistible, despite the hackneyed synth-pop production. Even better is "Thinking Man," a feminist's definition of what she wants in a man: both thinking and cuddling. Like Morrison, Armatrading is able to find the link between the two and turn it into an overwhelmingly joyful chorus. On "Friends Not Lovers" she confesses that she can't be friends with an ex-lover when her eyes keep traveling down his body. Her monologue is punctuated by piercing falsetto cries of "I want you back!"

That desire is translated into the sensual challenge of both the lyrics and vocal on the spellbinding ballad "One Night." "Strange" is an odd song indeed; as Armatrading confesses her embarrassed surprise at not missing an ex-lover, her big voice strains against the austere arrangement. "Moves" could have been a strong song, but it gets buried in the overproduction; "Love by You" is marred by Joe Jackson's overly ornamental piano work.

One can only hope that Armatrading will record the best of these songs on a live album soon, so we can hear them at their full potential. Better yet, maybe someone at A&M will wise up and let Armatrading produce herself; the last time anyone handled her well in the studio was when she produced her own 1979 EP "How Cruel."