Nashville is en fuego. The city’s filling up for the CMA Music Festival. The airport and highways are busily channeling music freaks out to Manchester for Bonnaroo. And everybody is flipping out about the Nashville Predators who will play for the Stanley Cup on Sunday night at home on Lower Broadway. It’s bigger, wilder, louder and richer than I ever imagined the city would be when I moved here twenty years ago. And it’s amazing. There’s just a glow and a wonder for most people, and if you want to avoid the whooping bridal parties on pedal taverns, there are plenty of places to hang out with good folks and good music that have nothing to do with that noise. Such as Music City Roots. On this week’s show, quite a few people found their way to the Factory for a bracing night of mostly solid country and bluegrass, with a stellar bluegrass-inspired musician from another country.