AmericanaFest is back in Nashville, running Sept. 13-17 for its largest and longest edition since 2019, inviting us all to consider again the variety and meaning of the music that lives in the Americana house. The category and community was born in the 1990s largely to preserve and protect traditional country music and country rock, but acoustic and traditional roots have been part of the mix from the beginning, ebbing and flowing in the mix. This year’s convention is an especially good one for lovers of old-time and bluegrass, or for making new fans, with a mixture of veterans and youth that suggest that trad is rad once again.