Martina McBride is one of the most recognizable voices in modern country music. During a career that spans two decades, she has sold more than 14 million albums and released a number of successful singles, including “Independence Day,” “Wild Angels,” “A Broken Wing” and “Blessed.” In a recent phone interview from her home in Nashville, Tenn., McBride discussed how her music has evolved over the years, the role of women in popular music and her current tour, which lands at Northern Quest Casino on Saturday night. SR: So, you’re about to start on your tour?