Americana, any way you like it
This special is a fascinating if futile attempt to squeeze a lot of round-peg music into one very square hole.
Americana is a rather noumenal genre to begin with - a borderless Shangri-La where Woody Guthrie and Hank Williams swap verses down at the Grange Hall.
But that apparently is too restrictive a concept for Nashville 2.0. The best explanation for the program's catchall premise is delivered by one of its primary talking heads, journalist Holly George-Warren.
"Americana," she observes, "is all that music that is uncategorizable."
Seconds later, singer Roseanne Cash is suggesting that Trent Reznor and Nine Inch Nails belong to said club. (To be fair, Cash is wearing a crooked smile at the time, so maybe she was just trying to stir the pot.)
It soon becomes apparent that Americana consists of whatever acts the producers have footage of. Fortunately, they have footage of some terrific acts.
The show pays homage, for instance, to Emmylou Harris and her sterling contributions over the years to roots music. There are some lovely stills of her early collaborations with the late Gram Parsons.
The performance footage is what makes this program well worth your time, including Harris dueting with Rodney Crowell on "Pancho and Lefty."
Other highlights include Buddy Miller jamming with Jim Lauderdale, the Avett Brothers doing "Live and Die," and a powerful rendering of "Barton Hollow" by the Civil Wars.
The Rise of Americana also shines the spotlight on some less-celebrated but nonetheless startling talents, such as Jason Isbell, Shovels & Rope, the James Hunter Six, and the Lone Bellow.
But it clearly doesn't know where to draw the line. Does Richard Thompson, supernal as he is, really belong here? Do the producers honestly believe that Brittany Howard's Alabama Shakes are playing Americana music?
The premise is something of a pig in a poke from the get-go. How can you identify Americana as a musical movement indigenous to Nashville when your headliner - Mumford & Sons - is British?
Actually, Marcus Mumford and his mates, who to a great extent are responsible for the popular resurgence of this type of traditional-sounding music, present another obstacle: Some of us could have happily gone several lifetimes without hearing another note from this self-important skiffle band. (Mungo Jerry was doing this more enjoyably 40 years ago.)
So Nashville 2.0 isn't really able to make its case, but it has the good fortune to include artists like the Mavericks and the Carolina Chocolate Drops. And that's great music no matter how you choose to label it.
Nashville 2.0: The Rise of Americana
9 p.m. Friday on WHYY TV12