It's hard to know what will happen when the string quartet Brooklyn Rider starts playing. Yes, these four guys love to play Debussy and Brahms, but they're just as likely to team up with a singer-songwriter or a Kurdish kamancheh player. Or write their own music. So we weren't sure what they'd do when they stopped by the NPR Music offices to play a Tiny Desk Concert. What we got was a bracing sample of their visceral fire.