After nine years as artistic director, Nadja Salerno-Sonnenberg is leaving the SF-based New Century Chamber Orchestra. She has earned, and the ensemble has organized, a farewell festival with three concerts: one of contemporary music on Tuesday night, one of workhorses with Vivaldi’s and Piazzolla’s Four Seasons of Buenos Aires, and on Saturday, a Gershwin evening featuring Melody Moore and a party afterwards.

Nadja's one word reason for attending Saturday's gala: "Booze." Nadja has a large personality, which I admit, has rubbed me the wrong way. Sometimes I've found her wanting of the necessary grace I expect from classical music performers. Of course, I'm wrong, first of all, to have assumptions on how she should act; and second, to focus on aspects that are irrelevant to her performance and her sound. Her statement during a panel discussion that composer Clarice Assad would write her a five-measures-long note because "she would make magic with it" lacked humble self-awareness. But who cares as long as she does make magic with it? And most importantly, she leaves behind an impressive legacy of promoting and commissioning new works of art from American composers, and creating beautiful music. She will tell you she's proud of it, and she's right.

The evening showed both sides of Nadja: the evangelist for modern classical music, displayed in music performance spanning a wide range of styles, all of them challenging yet approachable. And the brash take-no-prisoner speaker on a panel about, well, her work, which gave us the sound bites above.

For the former, the orchestra went through a series of pieces and excerpts from "featured composers" of the NCCO, an innovation Nadja brought to the ensemble. Each year, a composer would be commissioned to write a new piece for string orchestra for the last concert of the season, while the first presented an overview of the oeuvre of this composer.

On Tuesday, these pieces were grouped in small sets, each with its own theme. The first set (aptly, Prologue and Variations, by Ellen Taafe Zwilich and Memoria de la Luz by Lera Auerbach) found eerie textures and the variations in the Zwilich got the orchestra to display a variety of string styles over a strong rhythmic backbone. Auerbach's featured touching solos from the viola and Nadja.

Derek Bermels' Gliding over Algiers recalled the Adagio of Mahler or Barber, in a very classical style over an arpeggiated bass line, so much it was disconcerting that the composer is still very alive. Jennifer Higdon's Strings from her Concerto for Orchestra built short, off kilter melodies over a syncopated foundation.

Mark O'Connor's Song of the Liberty Bell was described as ur-American (and featured in a PBS documentary about the American revolution, but it sounded rooted in the British Isles with its folksy echos off bagpipes in the long pedals of the opening. Kudos to a string orchestra to evoke bagpipes, though.

Clarice Assad's Impressions is a theme and variation affair, with each variation shining a splotlight on each section of the string orchestra: first the violins in a fun romp of a hoedown, then the cellos, then the bass walking and walking, a twangy fiddle-like bluegrassy bit for the 2nd violins, and a sweet lyrical adagios for the violas.

The performance included a brash Strut by Michael Daugherty, another high energy pieces that passes the baton in between the sections and shows up their skills, and two of Bill Bolcom's Rags, a throwback to early 20th century Scott Joplin music, the first one soft and mellow, the second a happy note to conclude the concert that includes the string surprisingly successfully mimicking whistles.

Four Seasons