Anyone who's seen Sigur Rós in concert will tell you that it's nothing short of a religious experience — mainly due to the primal sound roars enveloping vocalist Jónsi's angelic croon. Because the Icelandic band is currently taking a breather, fans jonesing for such catharsis will have to settle for Jónsi's solo debut album, Go, which finds its vulnerability in silence instead of sound. Feathery acoustic guitars yawn and stretch as strings flutter in the background and Jónsi's unintelligible murmurs cohere in heartbreaking majesty. Daybreak-borne optimism and liquid sadness never sounded so lovely. The stripped-down Vermont trio Mountain Man unleashes perfect harmonies that have eerie undertones — the equivalent of a sweet little girl with horror-movie machinations.