At the end of last year, music-lovers were electrified by the announcement that 33 previously unknown works of Johann Sebastian Bach had been discovered in a manuscript at the Yale Music Library. The newly found works are chorale preludes for organ, a specialized taste even among lovers of Bach's music, and the interest of the music is largely biographical and musicological. But the discovery was undoubtedly the most significant event so far in the composer's tercentenary year.

Some observers have called it the most important musical discovery of the 20th century, which may be a bit of an overstatement. But the newly discovered material increases enormously the amount of Bach's music available from the years 1702 to 1710, when the composer was in his late teens and early twenties, and it gives audiences an opportunity to see the young giant flexing his muscles in a musical form he was to cultivate through much of his life and even on his deathbed.

Two recordings of this music have been rushed to the market by German organist Werner Jacob (on Angel DSB-3986, two LPs) and by American organist Joseph Payne, who has prepared and copyrighted a performing edition from the Yale manuscript (Harmonia Mundi HMC 5158). Both are labeled "World Premiere Recording" (a rarity, these days, in the thoroughly explored music of Bach) and they give sharply contrasting views of the music and the young composer. Attentive listeners, particularly if they are familiar with some of the Lutheran chorales that provide thematic material for this music, might notice that both records contain the same material. But the fact is not evident without serious concentration.

Jacob's approach is sober and scholarly; he plays the chorales in the order in which they appear in the Yale manuscript, and he presents all the Bach material in the manuscript, including five chorales already known from other sources. This completeness, together with his choice of rather slow tempos, means he takes up three LP sides with this material. Payne, who usually chooses significantly faster tempos, manages to get all the previously unknown material on one LP lasting more than 67 minutes. Jacob fills out Side 4 with the "Eight Little Preludes and Fugues" (BWV 533-560), attributed (not very confidently) to Bach.

Payne has rearranged the order of the pieces to suit his own tastes and needs -- a perfectly legitimate decision, since the works were composed to be played one at a time, as a part of religious services, not in a particular order as concert music. The traditional liturgical function of the chorale prelude is to present a hymn melody (with variations and elaborations) as an introduction to congregational singing of the thematic hymn. Strictly speaking, connoisseurs should play these little pieces only one at a time, preferably on a Sunday, choosing a hymn tune appropriate to that Sunday's liturgical motif and singing the hymn (in a group, if possible) after the prelude. But that might be carrying the quest for authenticity a bit too far.

For enjoyment as concert music, these works are best heard in segments, not all together, and it is almost a musical necessity to regroup them for continuity, balance and contrast. Payne has carefully studied the music in terms of concert presentation, and he succeeds remarkably in adapting it to a purpose for which it was probably not composed. He begins the performance with one of the most striking preludes, "Herzlich lieb hab' ich dich, o Herr" (Dearly I love Thee, O Lord), which comes near the end of the manuscript, and he makes it sound exciting in a brilliant, incisive performance with rugged rhythmic profiles. In his liner notes, Payne argues that the music might have been composed for harpsichord as well as (or rather than) organ and that its "suitability for domestic music-making cannot be discounted."

This is a between-the-lines plea for his kind of interpretation, which has a virtuoso, rather than an ecclesiastical, flavor. His argument (cramped into limited space) is not very convincing. But in performance, he does make the music sound like his description of Bach at the time it was composed: "A youthful genius; experimenting boldly . . . groping to perfect his musical language, shaping and expanding its structure and expressive power . . . with exuberance, flairful wit and poetic understanding of the hymn texts."

To their fans, Jacob will sound solid and reverent and Payne will sound brilliant and imaginative. To those who don't like them, Jacob may seem stodgy and Payne, flashy. On first hearing, there is no doubt Payne has a stronger impact; his technique is impressive -- he carefully shapes his registrations for variety, contrast and clarity, and he has a knack for making the chorale melody stand out in high aural relief amid the elaborations that surround it. His sound is considerably more colorful than Jacob's. It has a clear affinity to the sound one hears in Bach's secular orchestral works, but perhaps it is a shade too colorful for this essentialy sober kind of music.

Jacob makes the chorale preludes sound like what they are: music written to introduce congregational singing in a religious service. But Payne's approach also has some claims to authenticity when we consider the way parishioners of Arnstadt and, later, Mu hlhausen used to complain about the lavish, intricate, capricious and showy music of their young organist-composer. In terms of popular appeal, I think Payne's performance will be the overwhelming choice of most listeners who are not musicologists or devout Lutherans.