Mandolinist Chris Thile's splendid work with his prog-bluegrass trio, Nickel Creek, hardly prepared us for the ingenuity and ambition of his Punch Brothers project with classically trained, bluegrass-loving cohorts Gabe Witcher (violin), Paul Kowert (bass), Chris Eldridge (guitar) and Noam Pikelny (banjo). Thile managed to infuse larger and more complex musical structures with his newgrass style, far more effectively than most pop-to-classical crossovers, to produce a fascinating concept suite (The Blind Leaving the Blind, inspired by his divorce) and a striking new hybrid of roots-tinged chamber music.

Thile's band anchors the hippest trio of concerts in this summer's Chamber Music Northwest. In a series otherwise dominated by dead European male composers, the shows on Fourth of July weekend skew fittingly toward American music. In addition to its concert on Saturday, Punch Brothers plays American fiddle tunes at Thursday's show, which also includes music by two living composers: film score legend John Williams (Air and Simple Gifts, mimed by an all-star quartet at President Obama's inauguration) and Aaron Jay Kernis. The show also features Leonard Bernstein's early, spiffily jazzy Sonata for Clarinet and Piano and George Gershwin's Rhapsody in Blue arranged for piano duet.

Monday's concert includes a Punched-up arrangement of J.S. Bach's Brandenburg Concerto No. 3; contemporary American composer John Adams' dazzling 1978 Shaker Loops; a Haydn string trio arranged for mandolin, viola and cello; and Mendelssohn's piano sextet, which isn't quite six-eighths as powerful as his octet. Besides the Punchers, the concerts include Kernis, Portland composer-guitarist Bryan Johanson and the usual array of CMNW classical music all-stars. The venerable series' invigorating inclusion of modern American sounds deserves a fireworks display.

American music: 8 pm Thursday, July 2, at Reed College Kaul Auditorium, 3203 SE Woodstock Blvd., and 7 pm Friday, July 3, at the Gerding Theater, 128 NW 11th Ave. Punch Brothers: 7:30 pm Saturday, July 4, at Kaul Auditorium. Adams/Haydn/Mendelssohn: 8 pm Monday, July 6 at Kaul Auditorium, 8 pm Tuesday, July 7 at Catlin Gabel School, 8825 SW Barnes Road. 294-6400. $10-$50.