Fleet Foxes suggest an idyllic country pasture untouched by man and kissed gently by the sun. Largely lacking any electric guitars and accompanied by a bevy of traditional instrumentation including mandolin, fiddle, dulcimer, and harp, it harks back to the delicacy and graceful beauty of Sixties medieval-minded British folkies Pentangle and Renaissance, or more recently, Texas sextet Midlake. They’d already started to create a buzz in Seattle and on MySpace when their 2008 self-titled debut made them an indie sensation. That success and the accompanying expectations weighed heavily on chief songwriter Robin Pecknold, but they avoid the sophomore slump with their follow-up Helplessness Blues. It’s more darkly personal and the vocals are even higher in the mix, but it’s still abetted by achingly sweet melodies and the rich choral harmonies that made the debut so fetching. Overall, it’s a stirring, somewhat spooky effort venerating the human spirit in plush acoustic tones. With The Cave Singers.