Snow CoverSons of Serendip “Christmas: Beyond the Lights”

This classical-unto-R&B-unto-easy-listening band — made up of former Boston University schoolmates who auditioned together for “America’s Got Talent” in 2014 and went on to have a recording career — seems particularly built for Christmas albums: voice, cello, piano, guitar, and, most crucially, harp. “Christmas: Beyond the Lights,” with the Sons of Serendip’s arrangements of traditional songs — “O Holy Night,” “Let It Snow” and others — is alive with detail but silky beyond reason. It will make you spend money that you don’t have. BEN RATLIFF