Vocal recitals aren't a huge sell in Philadelphia, but for those who attend them, the sophisticated, wide-reaching program presented Monday by Finnish mezzo-soprano Monica Groop inspired no outward ambivalence - even with the name Schoenberg looming at the end of the program - and enough displays of deserved appreciation that she sang three encores.

Unlike recitals that are about communing with a beloved opera star, Groop's program of Schubert, Mahler, Bartok and Schoenberg (presented at the Kimmel Center by the Philadelphia Chamber Music Society) was a chance to hear her marvelously rich voice in some medium other than recordings, since her career is predominantly Europe-based.

Though her upper range isn't as controlled as in last year's recital here (louder volumes were unruly), the rest of her voice is more disarming than ever. Few sing a line with Groop's combination of expressivity and metal-edged cleanness. Her earthy low notes suggest a Nordic peasant (male, oddly enough) - in contrast with her glamorous presence.

That peasant quality put her in good stead for the whooping laughter of Bartok's Village Scenes, which would be as popular as Falla's Iberian Siete Canciones Populares Españolas, were the vocal lines not so bumpy. Groop so well understood the texts (Hungarian being related to Finnish) that she made great musical sense even in passages when the songs seem to spar with themselves. Add the smart contribution by pianist Rudolf Jansen, and you wanted to hold the moment: This may be the best-realized performance of this music you'll ever hear.

Four Mahler songs written before the composer was even 30 were rendered with perfection, though what that meant for the song "Hansel and Gretel" - with music that captures the meandering quality of kids at play more than the Humperdinck opera - was that the performance wasn't great because it was polished. Groop inhabited the characters while not neglecting storytelling elements.

The linguistic authority she displayed in five Op. 60 Grieg songs backfired slightly: You were even more aware of images too trivial to deserve their music. But her projection of German text in the Schoenberg Brettl-lieder - quasi-cabaret songs with a particularly sexy text by Magic Flute librettist Emanuel Schikaneder - sold the music's fusion of sensual pop idiom and harmonies of Brahmsian substance (pre-atonal, of course) in ways that made more sense than usual. Maybe more than it ever will.

No strategic leaps were necessary in Groop's last encore, Grieg's ever-durable "Jeg elsker Dig," which achieved ultimate directness through complete musical freedom.