Schubert Fantasie by Carolin Widmann and Alexander Lonquich Carolin Widmann, violin; Alexander Lonquich, piano. ECM New Series 2223 476 4546 SOMETIMES it is hard to understand why a work widely deemed a masterpiece fails to catch on with performers. But the reason Schubert's astonishing Fantasie in C for Violin and Piano (D. 934) is played infrequently is obvious to all performers who have tackled it: The piece is tremendously difficult. Though there have been some excellent recordings, a recent one offers an especially vibrant and commanding performance by two impressive German artists: the violinist Carolin Widmann and the pianist Alexander Lonquich. Written in 1827, the year before Schubert died, the fantasy is a 25-minute work in four movements, though the slow introduction returns in an altered state before the joyous finale. The score's difficulties are not of the virtuosic sort. The music, which hovers between the high Classical and early Romantic styles, is refined and almost mystical, starting from the serene opening Andante. A magisterial melody on the violin is cushioned by hushed tremolos, flittering rising thirds and delicate trills in the piano. The instrumental writing is awkward, especially for the piano. But it must be played with the kind of effortless grace and delicacy this duo demonstrates. The Allegretto that follows seems straightforward and animated on the surface. But the busy passage work in the violin and the leaping, dancing chords in this movement require the unstrained vitality and lightness that Ms. Widmann and Mr. Lonquich supply. Their technical refinement and musical insights continue through the glowing Andantino and the rousing finale. This rewarding album includes beautiful accounts of Schubert's Rondo in B minor and Sonata in A. The sonata is also pretty hard, especially the restless scherzo. You would not know this, though, by the fleet, crisp and sly performance from these superb Schubert players.