Blowing off both No Age at the Seaport and Brazilian Girls at the Bandshell, I took David up on his fairly emphatic suggestion when I saw him on Wednesday to check out singer-songwriter Krystle Warren at Zebulon last night. Wow – the Kansas City native literally sent chills down my spine with her deep, powerful voice and storytelling lyrics (esp. on “An American In Paris,” which might as well have been about my own recent stay there.) I can’t remember the last time a performer armed with only a guitar and her voice so totally dominated a room: it was like catching Joni Mitchell at the top of her game, back when she was playing the bars on Bleecker St. Assuming Warren’s on the same trajectory, what a privilege to see her here, now.