One of the more impressive vocal transformations of our time is the voice of American soprano Johanna Meier -- from what she listed as spinto soprano in the mid-1970s to what is now, a great deal of the time, a powerful Wagnerian voice.

Certainly, at least, the latter is what she is best known for today, either in her Isoldes at Bayreuth with Daniel Barenboim or in the gripping Sieglinde in the Met "Walku re" that she sang here last spring with Jon Vickers and James Levine.

Given this direction in Meier's development, it was just a matter of time before she would become better known as a lieder artist. Her rich and sometimes daring recital at the Kennedy Center's Terrace Theater Saturday night -- almost all of it in impeccable German -- clearly proved that in this respect Meier's time has come.

It came as no surprise that a stage actress of such intensity found her finest moments in the more directly dramatic of the songs. Nor was it unusual that a singer with such a large voice was more comfortable in the larger-scale works.

There was plenty of both.

Perhaps the finest moment in the evening's lieder came at the end of the regular program, in Richard Strauss' "Fru hlingsfeier" ("Spring Rite"), a remarkable image of blood sacrifice of spring maidens that was written at about the same time that Strauss was working with similar material in "Salome" and "Elektra." As Meier sang them, the repeated cries of "Adonis! Adonis!" were both thrilling and chilling. By the rules of song, this is a lied in a structural sense, but in fact it is more a brief scene.

A captivating warmer side of the German vocal literature for soprano followed immediately as the first encore, constituting an endearing expressive foil to the Strauss. It was that wonderful song "Ich schenk mein Herz" ("I give my heart") from Millo cker's operetta "Dubarry." The warmth that had been heard most of the evening relaxed into gracious gemu tlichkeit, a style that eludes most American singers.

There were moments of particular drama earlier in the program. Meier made a little tone poem out of Liszt's not so often heard "Uber allen Gipfeln ist Ruh" ("Over All the Hilltops There Is Peace"). Her set of Four Songs (Op. 2) by Arnold Schoenberg, with their harmonic hurdles and neurotic moods, were very skillful -- especially "Waldsonne" ("Forest Sun").

Oddly, Wagner's five "Wesendonck Songs," several of which are sketches for "Tristan," found Meier a bit more guarded in her singing, though "Im Treibhaus" ("In the Greenhouse") was full of jaded eloquence.

There also were arias by Handel and Haydn, and some Beethoven songs.

Mikael Eliasen was a careful pianist.