Emanuel Ax doesn't play Schumann so much as plumb him. You might quibble at times with the results, but it's hard to argue with this young pianist's impressive understanding and musical depth.

His recording of two popular showpieces, "Humoreske" Op. 20 and "Fantasiestucke" Op. 12, reflect the sort of levelheadedness that a geologist might bring to a volcano. The performances aren't flashy or viscerally exciting; they're detailed, cunning and so full of nuance that even those with a modest appetite for Schumann will find much to appreciate.

Both works, hallmarks of 19th-century romanticism, are typical of Schumann's keyboard creations: overflowing with lovely melodies lovingly repeated, lyrical wanderings and sliding modulations, plus stormy punctuations of fleet-fingered dazzle. This is music to emote by, and Schumann did more of that than most. In a letter to his faithful Clara, he described himself as "at the piano, composing, writing, laughing and crying, all at once."

Ax, by comparison, is always in full control. In the "Humoreske," something of a mood cycle, from brooding to whimsy and back again, he clearly presents his ideas, noting every swell of phrasing to get the most out of every melody. You may not like his singing along in the finale, but the piano technique is beyond question.

Ax's "Fantasiestucke," with its subtly shifting accents, passages of quasi-counterpoint and murderously difficult runs, is also a masterful job. But the second piece in the cycle, Aufschwung ("Soaring"), seems a bit muddy and earthbound compared to other versions I've heard. Ax is uncharacteristically heavy on the pedal here.

ON RECORD, ON STAGE THE ALBUM EMANUEL AX -- Schumann Humoreske and Fantasiestucke Op. 12 (RCA ARC1-4275).

THE CONCERT EMANUEL AX & YO YO MA -- Monday night at 7:30, with music for piano and cello in the Kennedy Center's Concert Hall.