The Argento Chamber Ensemble has been in business since 2000, but its players look as if they are only moments out of conservatory. They play that way too -- in a good way. Their technical polish lets them move easily through the rhythmic and harmonic thickets of the contemporary styles that are their specialty, but they also bring to their performances the kind of unsettled, restless energy that seems a special province of the young. Michel Galante, the group's conductor, is able to transform these warring qualities into readings that make even relatively static pieces sound dynamic and charged.
The ensemble's program at Merkin Concert Hall on Wednesday evening was planned as a survey of German and Austrian Expressionism, and that's mostly what it was. Kimmy Szeto's spare, woodwind-heavy chamber orchestra arrangement of the Prelude and Liebestod from Wagner's ''Tristan und Isolde'' offered a glimpse at the style's direct precursor. And a thrillingly gritty, acid-tinged account of Schoenberg's early Chamber Symphony No. 1 caught Expressionism in full flower.
Both these oldies (the Schoenberg had its premiere a century ago) were played after the intermission. The first half of the program looked at more recent works that arguably have roots in Expressionism, yet veer away sharply. Karlheinz Stockhausen's ''Kleine Harlekin'' (1975) hints at Schoenberg's ''Pierrot Lunaire'' but is a brighter, flightier work for solo clarinet with occasional percussion support. Carol McGonnell played it with graceful virtuosity, but it was hard not to compare her amusing but often marchy stage movement with the slinkier, more supple performances Jean Kopperud gave of the full version (''Harlekin,'' without the ''Kleine'') in the 1980s.
Georg Friedrich Haas's ''Nach-Ruf ent-gleitend '' (1999) and Wolfgang Rihm's ''Chiffre VI'' (1985) appropriate the dark hues and foreboding atmosphere of early Schoenberg, but these composers' works otherwise inhabit a universe far removed from Expressionism's heated emotionalism.
In Mr. Haas's score, the violin and high woodwinds play piercing tones that quickly evolve into microtonal clusters, against which a fragmentary, melancholy viola line creates a subdued narrative. And Mr. Rihm's work is a marvelously noisy tapestry of sound bursts, ranging from elephantlike horn blasts to the sepulchral growl of a contrabassoon.
To this entirely Germanic blend, the group added a French work at the last minute, Tristan Murail's attractively mysterious ''Feuilles à Travers les Cloches'' (1998). Its dependence on sound color and atmosphere rather than syntax and forward movement put it on common ground with the Haas and Rihm scores. But it was added to celebrate the release this week of the group's first CD, an all-Murail program, on the Aeon label.
That's a sensible enough motive, but you have to wonder: with a CD due out the week of its concert, why didn't the group devote its program to the French Spectralists, of which Mr. Murail is the best known, instead of the Expressionists?