She’s been called “the voice of Chicago” and “one of Chicago’s most treasured voices” by respectable critics in the Windy City, and this charming, Americana-based singer-songwriter indeed lives up to the spectacular reviews. After 20 years with her terrific backing group Trigger Gospel, Anna Fermin can look back on an incredible run of five critically acclaimed albums, several successful European tours, national festival showings, and many opening slots for big names in the business, including the group’s first gig as the warm-up act for Johnny Cash. They’ve just released You Belong Here, with all the original TG members including Springfield native Andon “Ted” Davis on guitar, as their first full-length release in eight years. Recorded in Hoffman Estates and produced by Trigger Gospel with John Rice, the album features songs penned by Anna and one from Texas Flatlander Butch Hancock. The show at WUIS is in the house studio and requires a Facebook RSVP because of the limited seating. On Sunday, local singer-songwriter Tom Irwin opens the Curve show with a short set.