There was a time, not too long ago, when some of us thought that digital stereo -- the compact disc -- was the ultimate medium for recorded music. It was the final stage in a long history of recording technology, dating back through more than a century of improvements that included scratchy 78-rpm shellac discs.

We were wrong. The CD has now had its memory vastly enhanced by DVD technology, which gives it a visual dimension, and super-audio -- SACD -- which offers four or five channels of high-definition digital sound. Suddenly, a nearly forgotten episode in recording history has returned.

In the 1970s, major record labels began recording their product in four channels and launched a campaign to sell quadraphonic sound to consumers.

But the analog playback technology then available to music lovers fell short of the potential in the master recordings, quadraphonic sound was abandoned and hundreds of programs recorded in four channels were released in two.

Still, the four-channel masters survived, and now, with the arrival of SACD for home systems, their time has come.

One company, PentaTone, founded in the Netherlands in 2001, has been right on top of this development, while the traditional major labels have been too busy lamenting their dwindling sales to take much advantage of the opportunity.

PentaTone's managing director, Giel Bessels, said in a recent interview with Fanfare magazine that in 2002 the label's founders "became convinced that surround sound would take over from stereo in the same way as stereo had replaced mono over time."

PentaTone has bet heavily on that theory and is in a position to win big. It has come into the American market with a brilliant catalogue of four- and five-channel recordings, some newly made but many of the best digitally remastered from Philips recordings that were issued in stereo and won glowing reviews. I have sampled some of these: Handel's 16 Organ Concertos complete on four discs with Daniel Chorzempa as soloist, Schumann's "Frauenliebe und Leben" sung by Elly Ameling, and Stravinsky's "L'Histoire du Soldat" and other orchestral works conducted by Paavo Jarvi. These were selected not only for their outstanding performances but for their varied sound perspectives. In every case the surround sound gave the performers a striking presence; it sounds like the standard of the future. Meanwhile, SACDs also play well in old-fashioned stereo, so listeners not yet wired for surround sound can collect them looking forward to an eventual equipment upgrade.

Other interesting recent discs:

Wagner: Siegfried (Opus Arte, 3 DVDs). Taped in Barcelona but originating in Berlin, this is the third episode in a video "Ring" cycle that promises to rank with the visually modernized Bayreuth set conducted by Boulez and the fantasy-medieval Metropolitan Opera set conducted by Levine. This production avoids identification with any historic period and plays the story out in a mythic environment. Music director Bertrand de Billy gets a powerful performance from the orchestra of Barcelona's Liceu opera house, and the singing is excellent throughout the international cast, notably from John Treleaven (Siegfried), Deborah Polaski (Brunnhilde) and Graham Clark (Mime).

Wolfgang Amadeus Mozart: Don Giovanni (TDK DVD). Riccardo Muti conducts the Vienna State Opera Orchestra and Chorus in a musically excellent but sometimes eccentrically costumed performance. Carlos Alvarez is a dashing Don Giovanni, and Adrianne Pieczonka, Anna Caterina Antonacci and Angelika Kirchschlager give first-class performances as his three female victims.

Stravinsky/Bach (ECM New Series CD). Violinist Leonidas Kavakos, one of the brightest lights of the younger generation, is unaccompanied in Bach's Sonata No. 1 and Partita No. 1, and brilliantly partnered by pianist Peter Nagy in Stravinsky's Duo Concertant and Suite Italienne. This disc has two basic motifs: technical challenge and the spirit of the dance. Both come vividly to life in fluent performances.

Nino Rota (Harmonia Mundi CD). Nino Rota's expertly crafted soundtrack music for some 50 films has won him a large international following. This wonderfully eclectic disc, with a bound-in 84-page booklet, includes circus music, a cancan, elegant waltzes, etc., in three compositions: "La Strada" Ballet Suite, Dances for the film "The Leopard" and Concerto Soiree for piano and orchestra. Conductor Josep Pons, the City of Granada Orchestra and pianist Benedetto Lupo do full justice to the material.

Danses: Laurent Korcia (Naive CD). Korcia is a young violinist with a sweet tone, a facile technique and a sure sense of what classical music will appeal to a mass audience: essentially, dance pieces lasting three minutes, more or less (except for Astor Piazzolla's longer "Cafe 1930" and Tchaikovsky's Valse-Scherzo). In pieces by Brahms, Dvorak, Ravel and others, his basic accompanist is pianist Jean-Efflam Bavouzet, but he is also partnered by guitars, a cimbalom, a bandoneon, etc., as the music's ethnic flavor requires.

Violinist Leonidas Kavakos brings works by Bach and Stravinsky gloriously to life on a new CD.