A subtle Sunday is in order. Go check out Berklee College of Music graduate and award-winning songwriter, Liz Longley. Longley performs at the Iron Horse Music Hall. Some think of Shawn Colvin or Paula Cole when they think of Langley, but recognize she has a voice all her own. “Her voice and tone, touched with the slightest of country inflections, pours out like clean, crystalline water. Still, she can roar like a waterfall or flow effortlessly along the bed her backing band lays down.” You can find out for yourself tonight at 7 p.m. Order an Iron Burger while you’re at it. Iron Horse Music Hall, 20 Center St., Northampton.