When a bluegrass act entirely abandons the genre's past to create something so novel that it may as well be called something else, it most likely is something else. (Not that that's necessarily a crime, I suppose I should add.) To those of us who have been listening to bluegrass for a long time, the style is a kind of musical comfort food. Everything that answers to the designation is not identical, of course, nor should it be. That would render it unlistenable, and innovation has always spiced the tradition. But it's innovation within the tradition, in other words the infusion of something implied, however dimly, in previous bluegrass material but now interestingly addressed and enhanced.

Nick Chandler & Delivered and Wildfire are sort of like that, at once familiar and fresh. The former feels something like a distant relative to Flatt & Scruggs, the latter to the Country Gentlemen, two foundational bands that helped define not only bluegrass but varying yet overlapping approaches to it. These modern groups, like their early antecedents, share a taste for fulfilling songs that do more than showcase instrumental skills.

They're also more inclined to choose covers than supply originals, which is fine with me; what matters is that they're good songs. (As I've had occasion to complain in this space, much of bluegrass songwriting is too often indifferent and forgettable.) Chandler's band delivers the fabulous "Lost River," written four decades ago by folksinger-songwriter Michael Martin Murphey (whose last name is misspelled in the credits) and built to last. Maybe the equivalent on Wildfire's side, though pushing a nearly opposite mood, is the playful "She's Crazy for Leaving," oddly credited to one "G. Charles Clark," usually known as Guy Clark.

Between them the bands spruce up country standards such as Don Gibson's "Oh Lonesome Me" (Wildfire) and Buck Owens & Red Simpson's "Sam's Place" (Chandler). I was never much taken with the country-pop hit-makers Alabama, but "Ride the Train," by member Teddy Gentry, is a perfectly satisfying train song, and Wildfire treats it just right, which is a solid choice for an opening cut. I have been a sucker for cornball hillbilly humor since I was a little kid, and Brink Brinkman's "Biscuits and Gravy" (Chandler) is certainly that. The singing is perfect for the occasion, too, in some ways calling up my all-time favorite backwoods jokesters, the glorious Lonzo & Oscar.

Throw in warm, expert picking and perfect harmonizing on top of superior material, and no bluegrass obsessive will find reason to complain. These two albums do bluegrass as it's supposed to sound: timeless but always itself.