Ornette Coleman's landmark album "Free Jazz" featured two quartets playing simultaneously. With four improvisers alone Saturday night, Test approximated the sound of that double quartet during its opening set at George Washington University's Phillips Hall.

Daniel Carter (trumpet, tenor sax, flute), Sabir Mateen (alto sax, clarinets, flute), Matthew Heyner (bass) and Tom Bruno (drums) got their start as Test by playing the streets and subway stations of New York City. But Test's start Saturday wasn't so unusual: With Carter on trumpet--not his strongest instrument--the quartet spent 15 minutes struggling to build up a consistent musical dialogue.

The conversation didn't take off until Carter switched to tenor sax and Mateen shifted to alto sax; then it was a grand sonic debate between two men. Carter's raspy tone was gritty but not guttural as he and Mateen almost constantly interwove horn lines; the former's filled with lively bursts in comparison to the latter's long, winding passages.

After the 25-minute opener, Test began a similarly energetic 35-minute improv with a quietly tense drum solo. Bruno's fidgety style--shuffling his sticks over the snare and across the cymbals, and clicking them up over his head--gave Test a subtly agitated undercurrent, but Heyner's bass flowed like a gentle river. Using drones, melodic arpeggios and surprisingly controlled bass lines, Heyner gave Test's soloists a solid foundation to jump from.

--Christopher Porter

Michel Dalberto

Michel Dalberto's concert Sunday afternoon at the National Institutes of Health was one of both reflection and momentum, finding a responsive audience filling almost every seat of the sizable auditorium. The French pianist, who has played with countless first-rate orchestras and received numerous awards, paired the Schubert filling the first half of his program with luminous works of Debussy and Ravel for the second.

For Schubert's Impromptu, D. 935, No. 1, Dalberto remained consistently mindful of the emotional peaks and valleys that lead transcendentally to the utter serenity of the close. Inflections of tone and tempo, along with detailed articulation, were tailored to convey a compelling sense of direction.

As Dalberto made his way through Schubert's late C Minor Sonata, D. 958, he sustained continuity as mellow contemplation repeatedly alternated with foreboding despair.

In the Adagio, the pianist found subtle ways to express a truly romantic artist's state of devastating, if self-imposed, isolation in full accord with the barren landscapes of Caspar David Friedrich, Schubert's older contemporary.

Dalberto's keyboard poetry captured the resplendent vistas of four of Debussy's "Images," while he approached Ravel's taxing "Gaspard de la Nuit" with greater immediacy and the composer's characteristic Iberian vigor.

--Cecelia Porter

Maire Brennan

It's highly unlikely that many fans attending Maire Brennan's performance at the Birchmere Sunday night were disappointed with her choice of songs. After all, the lead vocalist for the popular Irish ensemble Clannad clearly aimed to please. Yet it wasn't long before it became obvious that Brennan's ethereal soprano was its own reward--a haunting presence regardless of the tune or tempo.

After opening with a few songs from her fine new solo album, "Whisper to the Wild Water," Brennan gracefully moved back and forth through time, reprising ancient Gaelic tunes, solo album recordings and a mixture of Clannad hits and album tracks. The list of favorites included "Harry's Game," Clannad's signature hit, and "In a Lifetime," a song Brennan originally recorded with U2 vocalist Bono. Brennan has neatly integrated these songs into her own shows, but several lesser-known ballads, exquisitely rendered in English or Gaelic, were even more enjoyable and cast a quiet spell throughout the club. On other songs, inspired by the bloodshed in Northern Ireland, the singer infused the lyrics with a blend of melancholy soulfulness and lingering hope.

Brennan, who plays Celtic harp, is currently touring with a versatile ensemble featuring fiddler Sinead Madden and uillean piper Tiarnan O' Duinnchin. The band punctuated Brennan's atmospheric balladry with a lively collection of reels, jigs and hornpipes that helped bring the entire audience to its feet by evening's end.

--Mike Joyce

Lyric Piano Quartet

The sound of the Lyric Piano Quartet--violinist Glenn Dicterow, violist Karen Dreyfus, cellist Frederick Zlotkin, pianist Gerald Robbins--is one of unlimited power, precise intonation and acute attention to interior voicing. Its program Sunday afternoon at the Kennedy Center's Terrace Theater was anchored by the Brahms G Minor Quartet, a piece Arnold Schoenberg orchestrated because he thought it so tightly plaited that only an orchestra could clarify all the strands.

The piece as Brahms wrote it is made to order for the Lyric Quartet, which generated an almost orchestral sonority in the many big moments; yet throughout, one could hear deeply into their sonic fabric. Even the blazing, furiously paced presto ending had a lucent transparency that heightened Brahms's Magyar inflections and kept them airborne.

Composed in 1942, the Martinu Piano Quartet No. 1 is a peculiar amalgam of catchy, jazz-influenced syncopations--the froth of the Roaring '20s shaken and distilled, Czech folk tunes and much else that can be heard in shards and fragments rather than as concretely identifiable referents. But the music never feels derivative, or neo-something; it has heart and character. The searching performance got everything right.

The Turina Piano Quartet, Op. 67, is colorful, atmospheric and slight; it needed the ultra-refined advocacy it got from the Lyric. Furrow-brows might hear it as Spanish tap water with an olive or two for flavor, but this listener heard an immediately appealing impressionism that was more French than Iberian.

--Ronald Broun

Brentano String Quartet

At the Corcoran Gallery of Art on Friday, the Brentano String Quartet presented a program that highlighted the various ways composers since Haydn have manipulated this extraordinarily plastic musical form.

Robert Schumann's String Quartet in A Minor, Op. 41, No. 1, which opened the program, is a deeply romantic work full of contrapuntal detail. Schumann expanded the quartet's classical form to accommodate his long and imitative melodic ideas, but the result was music that sometimes seems unfocused. The Brentano players, however, achieved a unity of execution that clearly outlined the architecture while never losing sight of the music's inherent spontaneity.

Tan Dun's "Eight Colors for String Quartet" unfolded quickly, like thoughts in a daydream. Tan dispenses with the classical four-movement pattern altogether and opts instead for a series of eight fragmentary miniatures that call to mind romantic piano cycles, such as Schumann's "Davidsbundlertanze" and "Carnaval." Timbre is more important than form here, and the music is scored to imitate the nasal twang of Buddhist monks and Peking Opera singers. "Eight Colors" demands flexible intonation and an actor's sense of drama, and the Brentano Quartet could not have offered a more convincing interpretation.

Mozart's String Quartet in G, K. 387, which closed the program, was rewarding in every way. The Brentano gave an elegant and spirited reading of this work, achieving a full and rich tone that was beautifully blended without sounding homogenized.

Formed in 1992 at the Juilliard School, the Brentano String Quartet--violinists Mark Steinberg and Serena Canin, violist Misha Amory and cellist Nina Maria Lee--is still a relatively young group. But the foursome has already evolved into a worthy first-class ensemble.

--John Pitcher