Rhino has pulled together a pair of sets - the matter-of-factly titled "R&B Box" and "Soul Train Hall of Fame 20th Anniversary" - that boogie and bump through about a half-century of black music, from World War II to the present.

By far the most ambitious - 108 songs, six discs, five hours of music - "The R&B Box" is an incredible collection. That expansiveness, however, is also its primary flaw, because every artist, major and minor, gets basically the same consideration and emphasis (one track), and at times the choices are less than sterling ("634-5789" for Wilson Pickett? "Mickey's Monkey" as the entry representing pop poet Smokey Robinson and the Miracles?).Each volume surveys a different era, beginning, aptly, with "the grandfather of rhythm and blues," Louis Jordan's "Five Guys Named Moe," from 1943, and rolling through the years to the Spinner's 1972 hit "I'll Be Around." Volume 1 is subtitled "Jumpin' the Blues (1943-1950)"; Volume 2 "Teenagers Are Diggin' It (1951-1954)"; Volume 3 "Rockin 'N' Rollin' (1955-1956)"; Volume 4 "Goin' Nationwide (1956-1961)"; Volume 5 "Soul Brothers & Soul Sisters (1961-1965)"; and Volume 6 "The End of the Golden Age (1966-1972)."

For years this genre had no name; the term "rhythm and blues" is credited to noted producer-commentator Jerry Wexler, who came up with it in the late '40s to more acceptably describe a broad category of "race music." And broad is an understatement. Listen to the "R&B Box" and what do you hear? Swing, honky tonk, bop, blues, jump, doo wop, gospel, sweet soul and rock and roll. It isn't an easy thing to find an umbrella that shelters a welter of styles emerging from cities as diverse as New York, Chicago, Los Angeles, New Orleans, Memphis, Kansas City, Detroit, Philadelphia and more than a few other places in between.

This entertaining amalgam is also educational - "The R&B Box" is virtually a documentary if you read the accompanying booklet essays while enjoying the tunes. Peter Grendysa's observations on the rise of rhythm and blues and Billy Vera's song-by-song anecdotes are particularly enlightening.

But the avalanche of music is the thang, from the harmonies of the Clovers and the Chords to the originals of such songs as "Hound Dog" (by "Big Mama" Thornton), "I Hear You Knocking" (Smiley Lewis) and "Gypsy Woman" (the Impressions). And occasionally the sequence is simply glorious., as in the middle of the fourth volume, when Jackie Wilson's "Reet Petite (the Finest Girl You Ever Want to Meet)" is shortly followed by the likes of Jerry Butler's "For Your Precious Love," Clyde McPhat- ter's "A Lover's Queston" and, best of all, Etta James' "At Last" and Ben E. King's "Spanish Harlem."

"You've got to win a little," the Five Keys sang in 1951, "you've got to lose a little, and always have the blues a little. That's the story of, that's the glory of love."

And that's pretty much the story of, and the glory of, R&B as well.

- IN HIS NOTES for "The R&B Box," Billy Vera eulogized rhythm & blues and soul as a fading genre. "Soul Train Hall of Fame" submits a second opinion. How can the form be said to be dead when Gladys Knight and the Pips' "Midnight Train to Georgia," Marvin Gaye's "Sexual Healing" and Ashford & Simpson's "Solid" are still to come in the decades ahead?

This collection - packaged in a velor-covered case - is a classy tribute to Don Cornelius' syndicated TV dance program "Soul Train." In fact, each of the three discs kicks off with a theme used in the show: MFSB's silken "TSOP (The Sound of Philadelphia)," O'Bryan's "Soul Train's A'Comin" and George Duke's "Soul Train Theme," the '80s update of "TSOP."

Cornelius, a disc jockey turned role model, began the show in Chicago before beaming the program to metropolitan areas across the country from Los Angeles. He saw "Soul Train" as a vehicle for black culture, says annotator Danyel Smith: "Young black people, on television every weekday, dancing to black music. There was a black host. This was new. The low-budget production was of no matter - `Soul Train' was amazing, seductive, and validating."

Cornelius admits he is always leery of fads like disco, but in fact disco and the beat, wordplay and attitude of hip hop do insinuate themselves into the "Hall of Fame" via such performers as Donna Summer and Naughty by Nature. Still, most of this collection represents two decades' worth of soul and dance classics, and has actually a far higher ratio of certifiable hits than "The R&B Box": the 59 "Soul Train" tracks include 38 R&B No. 1's, and a dozen that reached the summit of the pop charts as well.