The St. Olaf Choir gave maybe its most demanding, progressive program in years this Sunday at their Spring Concert in Skoglund Auditorium. The choir ably tackled an unprecedented amount of difficult literature, despite some lackluster performances from an uncharacteristically taxed ensemble. The program was divided into four sets by historical era. The first set, five sacred Renaissance pieces, showed a new side of the choir and was probably the strongest performance that night. Conductor Robert Scholz's fresh renditions of this era were a welcome departure from the choir's textbook sound. He gave new attention to a period-authentic simplicity that avoided the choir's cliched tendencies without losing their brilliant clarity or energy. Their execution of the stirring Gabrieli motet O magnum mysterium and Ascendit Deus by Peter Philips showed their hard work. It was a welcome change from Conductor Anton Armstrong's predictable, though well-loved, sound. The inner two sets featured the choir's most challenging lineup in years. Though an admirable endeavor, it was arguably their weakest performance of Classical and Romantic music in as long. After an energetic and poignant Bach cantata, the remainder of the inner sets had some ups, but never approached the choir's full expressive potential. This was due in part to the sheer volume of music the choir had to memorize. The marathon Brahms motet Warum ist das Licht gegeben dem Mühseligen kept their minds occupied with remembering words rather than interpreting them, evidenced by a lack of subtlety in line shaping and dynamic contrast, which the choir usually has under control. Despite a fairly sloppy performance by the choir's standards, to take on pieces like Komm, heil'ger Geist, a late Romantic work of Georg Schumann, was a bold step for this talented choir. The final set featured refreshing pieces, including nine written within the last 20 years. Most notable was the choir's first premiere in years of the dark Angus Dei by Resident Composer Justin Merritt. Other highlights were Francis Poulenc's Messe en sol-majeur, and Morten Lauridsen's Sure on this Shining Night, both sung expertly. The choir finished on an uplifting note, offering a spiritual, We Believe That This is Jesus, which featured a passionate solo by senior Skip Napier. The concert was not the choir's best, but the group took admirable risks. Hopefully this adventurous spirit will be part of next season's programming.