Separately, Salmon and Seekins are strong, sharp-voiced musicians, with songs inspired by their colorful and unusual backgrounds. Together, they’re something bigger: a soulful, countrified duo whose music nods not only to America’s rural pockets, but also to the world at large. Appropriately, the group takes its name from the real-life Surrender Hill in South Africa, where the Anglo-Boer War came to a close. After all, this a band of songwriters who’ve fought their own battles and suffered their own scars, only to surrender to — and find peace with — each other.