Sam Beam is no stranger to sharing the stage: The beard better known as consummate soloist Iron & Wine has lent his melatonin tenor to collaborations with Calexico (In the Reins) and Band of Horses' Ben Bridwell (Sing Into My Mouth). But Love Letter for Fire (Sub Pop), his current set of duets with Jesca Hoop, is the first on which he shares writing credit (he penned every song on In the Reins, and Sing into My Mouth contains all covers). Hoop, a relative unknown whose break came while working as a nanny for Tom Waits, seems a peculiar choice as co-pilot — until you hear them sing together, and it becomes difficult to imagine the pair ever parting. Love Letter for Fire has a few tracks ("Midas Tongue," "Bright Lights and Goodbyes," "Valley Clouds") that are basically Iron & Wine songs, with Hoop sitting in for Beam's regular foil, his sister Sarah. Interestingly, it has more where Beam is Hoop's support. On "The Lamb You Lost" and "Chalk It up to Chi," her unusual vocal phrasing recalls Laura Marling, an artist in many ways Hoop's inverse. Marling arrived in California from England and has made increasingly mazelike albums; Hoop moved from California to England and, in matching Beam warmth for warmth, has found a larger audience. Marlon Williams opens. Tickets $30-$50.