"Sumptuous" may be the best word for the sound of the Royal Philharmonic Orchestra. It is a sound notable for richness and depth, almost as much as that of the Vienna Philharmonic. Whatever may be the players' state of mind or financial condition, they produce a collective tone that is comfortable and relaxed.

This sound contrasts sharply with that of most American orchestras, which tend to be tense and athletic, often giving the impression that they are driven to their limits. The difference can be heard readily in two recent recordings, conducted by Andre' Previn and recorded by Telarc -- a company with a recording philosophy that lets each orchestra's distinctive sound blossom without interference by knob-twiddling engineers.

In Gustav Holst's "The Planets" (Telarc CD 80133), the opening "Mars" section has an elemental strength that is based on precisely controlled tonal nuance rather than raw energy or rhythmic tension. The "Battle on the Ice" section of Prokofiev's "Alexander Nevsky" resembles Holst's "Mars" in some ways, and with the same conductor on the podium in both records, the same recording engineer (Jack Renner) in charge and a lot of the same recording equipment in use, one might expect the similarities to be emphasized.

They are not. Previn's other orchestra, the Los Angeles Philharmonic, sounds supercharged -- driven, but magnificently driven. Its effort -- its muscular strain -- can be heard in the sound of its music-making, while the Royal Philharmonic, playing one of the century's prime orchestral showpieces, makes it sound effortless.

Part of the effect certainly can be credited to the differences between Holst and Prokofiev. And the almost terrifying immediacy of the L.A. Philharmonic's sound may reflect the presence of the new "Colossus" recording processor at that session.

But mostly, we are hearing a contrast between the sounds of two orchestras with the same conductor but strikingly different personalities. It is not a question of better or worse; both orchestras are outstanding and the music (which includes the "Lieutenant Kije" Suite on the Prokofiev disc) is well-served all around. In an age when orchestras everywhere are coming to sound more and more alike, Previn deserves credit for respecting and fostering this kind of individuality.

Previn has also recorded Prokofiev with the RPO -- "Peter and the Wolf," with himself as narrator -- on Telarc CD 80126. The orchestra does justice to all the tense moments of this taut little music-drama, but the tension is tonal, rhythmic and harmonic; never does the orchestra sound as overworked and underpaid as London orchestras are known to be. It is even more at home in the music of Benjamin Britten, which fills out this disc: the "Young Person's Guide to the Orchestra" (played without a narration) and the "Courtly Dances" from "Gloriana." The playing and sound are superb throughout.

The Royal Philharmonic's special affinity for British composers dates back to the time of its founder, Sir Thomas Beecham. That affinity is gloriously present in two recent recordings, under Previn's baton, that also let listeners enjoy some excellent symphonic marches.

The marches may be simply fillers because Elgar's "Enigma" Variations (on Philips 416 813-2) and Walton's brilliant Symphony No. 1 (on Telarc CD 80125) do not exhaust the capacity of a compact disc. But Walton's two coronation marches, "Orb and Sceptre" (for King George VI in 1937) and "Crown Imperial" (for Elizabeth II in 1953) are splendid, stirring music; they fit comfortably with the sometimes Sibelian grandeur of the symphony, and they are wonderfully performed and recorded.

Elgar's five "Pomp and Circumstance" Marches, particularly the first, are probably better known and may motivate more sales than the "Enigma" Variations with which they share the Philips disc. But the "Enigma" performance is an excellent demonstration of the RPO's versatility, polish and sheer ease of execution. The music is nearly as nimble in its changes of mood and style, as extreme in its range of expression as "The Planets." It gives a great orchestra numerous modes for displaying its greatness, quickly and efficiently; three of the variations must make their impression vividly in less than a minute, and most of them last less than two. Previn steers the orchestra through this series of cryptic epigrams with an assured touch.

The most memorable of the RPO's recent recordings are undoubtedly those (already reviewed here) that have been issued on its own RPO label, distributed in the United States by MCA Classics. Recorded because the orchestra itself felt the need for the recordings to exist, not because they fit into any company's marketing plans, the first three RPO discs have all featured large-scale works for soloists, chorus and orchestra: Michael Tippett's "A Child of Our Time" (MCAD 6202); Faure''s Requiem with Bernstein's "Chichester Psalms" (MCAD 6199); and Walton's "Belshazzar's Feast" with his suite from the great "King Henry V" sound track (MCAD 6187). All are examples of musicianship at its highest level and worthy of serious attention.