Fifty years is a significant milestone for a musical ensemble, perhaps never more so than in the present day, when fundraising and audience building are, alas, increasingly challenging. The Oregon Repertory Singers, which began life in 1974 as the Portland Chamber Singers, has charted a course in their history with both a thoughtfulness and sense for adventure that should serve as a model to other groups. It has cultivated collaborations with other Portland-area institutions, and has struck a highly compelling balance of repertoire that includes many popular choral works as well an impressive amount of contemporary music. Its first CD, released in 1993, featured music by Arvo Pärt and Lou Harrison. By its third decade, the ensemble began its first commissions.

This commemorative CD is clearly designed to reflect that overall philosophy, with a bias towards the traditional side. A goodly chunk of the material comes from the ensemble’s annual “Glory of Christmas” concerts, but this is not the typical happy holiday fare (thankfully), but beautiful, often somber material, opening with a sotto voce work by Ēriks Eŝenvalds that directs the choristers to play tuned wine glasses, à la Franklin’s glass harmonica. Delectable music from two of the big names in contemporary choral writing, Eric Whitacre and Morten Lauridsen (who is a Portland native), is included. The highlight of the album is a performance of the Sunrise Mass by the young Norwegian-born composer Ola Gjeilo. The four-movement work eschews the traditional sections of a Mass with his own titles: “The Spheres,” “Sunrise,” “Identity,” and “The Ground.” It is a richly atmospheric and unabashedly tonal work that deserves a wider audience. The accompanying ensemble betrays little sense that it is a high-school-aged chamber orchestra—its sound is utterly professional. The Oregon Repertory Singers would do any musical community proud. The recorded sound is spacious.