Portraits in Blue.

THE music coming in on the car radio was Gershwin's Rhapsody in Blue, but it was being murdered. The slow tempos were too slow, the fast too fast, the piano passages overstated, and schmaltz was destroying the crisp evocation of 1920s jazz. "Andre Previn," I said to my wife. And so it was, as it was eventually announced. The Rhapsody has long been the victim of attempts to give it long-hair vapors, and those who really love the piece should turn to the original Paul Whiteman rendition with the composer at the piano, which the Smithsonian issued in its historic Gershwin compendium.

Comes now a new recording which moves in another direction. In Portraits in Blue (Sony SK 68488), the very fine young jazz pianist Marcus Roberts has added to the Rhapsody in Blue a series of strictly jazz improvisations based on Gershwin's score. What Gershwin might have felt about this is anyone's guess, but I suspect he would have approved. For the Roberts jazz cadenzas are fine in themselves, and appropriate to the score; they give the work contemporaneity, and also bring it back to the composer's intent. Included on the CD is an orchestration by William Grant Still, the great and forgotten composer and arranger, of James P. Johnson's piano score of his "opera" Yamekraw, a work that has been completely and undeservedly forgotten. With Roberts in these efforts are the Lincoln Center Jazz Orchestra and members of the Orchestra of St. Luke's, Robert Sadin conducting.

A new recording of Man of La Mancha (Sony 46436), the musical comedy that opened quietly off-Broadway in 1965 and became a runaway international hit, introduces its program notes with a quotation from the Spanish philosopher-poet Miguel de Unamuno: "Only he who attempts the absurd is capable of achieving the impossible." They are good words to bear in mind when considering that combination of mysticism and buffoonery, El Ingenioso Hidalgo Don Quixote de la Mancha -- a book that seems to have been supplanted in high-school curricula by Erica Jong's Fear of Flying. What made Man a great hit was its rejection of the all-elbows "modern" tonalities with which Leonard Bernstein and others had corrupted Broadway musicals, and its return to the kind of melodic and tuneful richness of, say, My Lady. Don Quixote is very nicely sung by Placido Domingo, who seems much more comfortable singing light classics and Latin popular music than he is on the stage of the Met. An able cast and Paul Gemignani at the helm of the American Theatre Orchestra give a solid performance.

It was the French poet, Theophile Gautier, inspired by Heine's De l'Allemagne, who with librettist Vernoy de Saint-Georges conceived the ballet Giselle. With the music of Adolphe Adam, it became one of the great achievements of Romantic ballet. Its swinging cantilenas and dance rhythms capture the mood of Heine's passionate dancing maidens who "waltz pitilessly . . . in a mist softened by German moonlight" and die before their wedding day. It is a lovely score lyrically traversed by Anatole Fistoulari and the London Symphony Orchestra (Mercury 434 365-2). Included in this two-CD set is that rollicking war horse, Jacques Offenbach's Gaite Parisienne, with the Minneapolis Symphony Orchestra conducted by Antal Dorati.

The two great sources of Western music have been the Catholic liturgy and the songs of the folk. Yet though Spain produced the finest of early liturgical composers, Tomas Luis de Victoria, and the great outpouring in the fourteenth and fifteenth centuries of religious and secular song -- the cantigas and the romances -- as well as the later gypsy inspiration of the flamenco and the cante hondo -- Spanish music became tied to the guitar, and its tonalities and melodic cast continue to derive from the cuadro flamenco and the cornets of the bull ring. It is in this context that we must measure Joaquin Rodrigo, born in 1901, and still alive today. His Concierto de Aranjuez, for guitar and orchestra, and his Concierto Andaluz, for four guitars and orchestra (Mercury 434 369-2), are works of which it can be remarked that they speak beautifully what others have been saying in the last nine or ten decades. What this record brings is the fine playing of the four brothers Romero, guitarists par excellence.

In the popular field: Aznavour: Greatest Golden Hits (Angel 33703) and Come Rain or Come Shine: The Harold Arlen Songbook (Philips 446 818-2). Charles Aznavour, a darling of French films and the Paris boites, sings English translations of his Gallic hits, which lose their verbal wit. But there is Aznavour's delivery, though not quite what it is in the French, and this still appeals.

The Harold Arlen collection prompts the question, Why? It forges together Andre Previn and Sylvia McNair, who bring out the worst in each other. These songs have been superlatively recorded by Ella Fitzgerald, Judy Garland, and Lee Wiley. Miss McNair has a good voice, but she tends to be flat, she takes the ballads too slowly, and her departures from the melody are disastrous. Harold Arlen wrote for Broadway, Hollywood, and Tin Pan Alley, and he was a good vocalist. His songs never strayed from a jazz beat, and they all had meaning -- but neither Previn nor McNair understands this. With a good accompanist, Miss McNair might do very well, but the Previn schmaltz does her in.

The New Orleans marching bands would play dirges on the way to the cemetery and at the graveside, then turn their aprons and beat it out, perhaps to send the departed happily on his way. The Preservation Jazz Band brought the generations together in re-creating the music of the early jazz era unencumbered by later sophistication. It now offers In the Sweet Bye & Bye (Sony SK 62363), which gives us this religious side of New Orleans jazz --both the hymns and the back-to-town pacers. Many of them sound much like that New Orleans march Louis Armstrong revived, "When the Saints Go Marching In," but they all reflect the harmonies of pre - World War I jazz. These are fine burying tunes and you may want them for the next funeral -- yours or mine.