The world's archives of recorded music are now going through a rite of passage -- the most stringent and far reaching since the early 1950s. Then, the question was which music from the era of 78-rpm recording would be transferred to the new LP format. Today, with LPs fading rapidly into history, the question is which material from the past will be reissued in the new compact disc format.

It is not quite a question of survival; equipment for playing LPs is still abundant and probably always will be available in specialized archives. Moreover, there is no solid evidence, so far, that the tape cassette is headed for oblivion along with the LP. But the CD is clearly destined to become the standard nontape format for commercial recordings, and records that don't make it to CD are destined to become antiques and collector's items.

The best news on this front comes from Nonesuch Records, which has just reissued some of its most successful records from the 1970s on compact discs. All eight in the first shipment are, in one way or another, classics and standard-setters in the art of recording, and in the transfer to CD, Nonesuch has managed to enhance the originals. Each of the CDs offers more music than the LP, and the sound, which met the highest standards of its time, is better than ever -- usually close to the highest standards of today.

More than any other single factor, Joshua Rifkin's recording of piano rags by Scott Joplin (Nonesuch 9 79159-2) launched the Joplin craze that raged through the 1970s and still continues. Some listeners complained about Rifkin's sedately classical tempos and phrasing, but a glance at the sheet music makes it clear that Joplin wanted his music played that way, and the interpretation established the music's classic status. The new CD contains all the contents of the historic Vol. 1 in this series, and the best halves of Vols. 2 and 3.

"After the Ball," a collection of turn-of-the-century songs by mezzo-soprano Joan Morris with pianist William Bolcom, is one of the most perfectly executed collections of musical nostalgia ever offered the public. On Nonesuch 9 79148-2, it sounds better than ever, and the CD has six splendid selections from the couple's follow-up album, "Vaudeville." Equally well presented are the "Songs by Stephen Foster" performed by mezzo-soprano Jan DeGaetani, baritone Leslie Guinn and pianist Gilbert Kalish on Nonesuch 9 79158-2. The CD contains all of Vol. 1 and 60 percent of Vol. 2 from the original LPs.

Both "After the Ball" and the Foster disc are essential for any serious collection of Americana. So is "Cornet Favorites" (Nonesuch 9 79157-2), although a couple of selections were composed by Europeans. It represents the kind of music that was played to while away summer Sunday afternoons on bandstands all over America in the early years of this century, specifically, the numbers given star soloists while colleagues in the band caught their breath. The performer on this disc is Gerard Schwarz, an outstanding trumpeter before becoming a noted conductor, and he catches precisely the blend of relaxed enjoyment and technical brilliance the music requires. The CD also contains five selections from the follow-up collection, "Cousins."

Nonesuch has always had a taste for the best contemporary music, and this penchant is represented in two CDs remastered from classic LPs. On 9 79149-2, George Crumb's evocative song cycle "Ancient Voices of Children" is presented with the work from a separate LP, his "Music for a Summer Evening," for two amplified pianos and percussion, Part 3 of his history-making "Makrokosmos" series. Both performances are definitive (Jan DeGaetani is featured in "Ancient Voices of Children"; pianists Gilbert Kalish and James Freeman in "Music for a Summer Evening").

Two thematically compatible LPs also are joined in "Percussion Music" (Nonesuch 9 79150-2), performed by the New Jersey Percussion Ensemble. Classical percussion music is clearly not to everyone's taste, but if your collection is going to have only one record in this category, this is the one to have. It contains several landmarks in the field (by Edgar Vare`se, Michael Colgrass, Henry Cowell and Charles Wuorinen), it demonstrates the variety of textures that can be woven with percussion, and it is superbly performed and recorded.

Two outstanding piano records complete the list. In his Debussy recordings for Nonesuch, the late Paul Jacobs radically altered the traditional, misty approach to the composer's piano works. His no-nonsense interpretation is nowhere more appropriate than in the two books of Etudes, which he performs on Nonesuch 9 79161-2. The disc is filled out with a fine, previously unreleased live performance of "En blanc et noir" with Gilbert Kalish on the second piano. Kalish is featured alone in excellent, well-recorded performances of five Haydn piano sonatas (Hoboken Nos. 36, 40, 41, 49 and 50) on Nonesuch 9 79162-2. His Haydn is not such a dazzling revelation as his Joplin, but only because the composer is better known. He does find a depth in this music that eludes many.

Other CD reissues:

Festival Hoffnung. (Harmonia Mundi HMC 90768). Gerard Hoffnung was a tuba player and cartoonist specializing in musical subjects who sponsored several comic music festivals in London during the 1950s. This CD, compiled from several LPs commemorating these events, includes a tuba arrangement of a Chopin mazurka, the most surprising performance Haydn's "Surprise" Symphony has ever had, Beethoven's great, apocryphal "Leonore No. 4" Overture, a Mozart horn concerto movement with the legendary Dennis Brain playing a garden hose, and the "Concerto Popolare" in which the orchestra plays Tchaikovsky (mostly) while the soloist plays Grieg (mostly -- there also is some Gershwin, the "Beer-Barrel Polka" and other stuff). It is heartwarming to see this vintage material marching bravely into the digital era.

Fandango, Vols. 1 & 2. Carlos Montoya, guitar (Bainbridge BCD8103). The great flamenco player's guitar has never sounded better than in this remastered analog recording from 1980. As the title indicates, material that originally filled two LP records is held comfortably on a single compact disc. The same is true of "The Digital Fox, Volume One and Volume Two" (Bainbridge BCD8104), another in this company's first sortie into classical repertoire. These performances of two Bach selections and some of the basic French organ repertoire were widely admired in a hi-tech analog LP set, but the same material was also recorded digitally and sounds splendid on CD. A third Bainbridge CD (BCD8102) contains the last recording by Arthur Fiedler and the Boston Pops: Tchaikovsky's "Capriccio Italien" and Rimsky-Korsakov's "Capriccio Espagnol" in bright, vigorous performances that will be treasured as a memento of that musical team in its prime.