Walk past walls lined with guitars, mandolins, banjos and dobros and you get to the beating heart of McCabe’s Guitar Shop: the live performance stage. Bryan and I went to McCabe’s on Friday to see Ivan and Alyosha, a band from Seattle that actually features three guys, none of whom are named Ivan or Alyosha. (The name, they explained, refers to two Brothers Karamazov, since two of the members are brothers.) Bryan is going to be mixing some of their songs, so he wanted to hear their songs live. They play sweet, lilting melodies limned with perfectly blended harmonies. The effect is something between Paul McCartney, Simon and Garfunkel and Wilco. During intermission, the band members chatted with guests next to a rack of song books and guitar straps. A girl with her parents snapped pictures with them. I guess it’s this kind of humbleness and intimacy that McCabe’s space is designed to foster.