JAZZ SPOTLIGHT : DIANE SCHUUR AND B.B. KING ; “Heart to Heart”; <i> GRP</i> ; ***

This is a curiosity in at least two senses. King, arguably the world’s most popular blues singer, doesn’t deliver a single blues number among the 10 tracks; he is presented primarily as a ballad singer. His guitar is heard too infrequently. As for his partner, she has some creditable moments here, and relatively few attacks of the synthetic hysterics to which she is subject.

The rapport between the pair works well, though there is not much of an attempt to harmonize effectively. The backups vary widely from cut to cut, with background vocals here and there and capable arrangements by Doug Katsaros. Some of the songs are odd choices, however. An example: the Astaire-Rogers 1936 hit from the Irving Berlin songbook, “I’m Putting All My Eggs in One Basket.”

For a sampling of how this team works best and least pretentiously, listen to the first chorus of “At Last,” with Schuur and King taking alternate eight bar strains. True, after B.B.’s guitar solo there’s a duet passage in which Schurr goes off the rails briefly, but it’s still agreeable listening. Albums are rated on a scale of one star (poor), two stars (fair), three stars (good, recommended), four stars (excellent).