As the number of truly independent radio programmers seems to dwindle even further on the terrestrial dial, broadcasters have a reason to celebrate as David Dye’s World Cafe marks its 20th anniversary on Philadelphia’s WXPN.

The tastemaking show will commemorate the milestone with a two-day concert at the end of October featuring John Hiatt, Feist, Dawes and the Band’s Robbie Robertson, prefaced by a series of 20 retrospective broadcasts. Yet Dye will also carve out time in each show for a new artist spotlight — an appropriate format for a show that has given key early exposure to the likes of Coldplay and My Morning Jacket while also delving deep into blues and jazz catalogs.

“Sometimes they’re so big and so obvious,” Dye said, recalling the acts he’d had a hand in breaking. “Jeff Buckley would be one. And we were earlier than early with Norah Jones, and man, you could tell right from the beginning… Looking back, those seem like no-brainers, but at the time they weren’t.”

But Dye still hasn’t found the magic formula for new artist discovery. “Sometimes it’s difficult to find anyone with exclusivity who’s any good. I can play a lot of new music, but is it gonna have any staying power? Is it going to be something where our audience says, ‘Oh I heard of them when’?”

All the same, “It still always starts with me listening to something and saying, ‘Wow.’ ”

Dye’s show is syndicated on 185 public radio stations, and he shows little sign of losing his touch. Yet Dye casts a bit of a wary eye on the future of the format in its current state.

“It’s hard for me to be really optimistic,” Dye said. “But that said, I can point to those people who really give a quality niche product of some sort — be that a quality hip-hop station, or something like what NPR music does, or what we do.

“I do worry about exclusively Internet-based radio, just in the sense of making sure that stations are connected with some sort of terrestrial source or publication. A Pitchfork radio station might do really well, for example. But you have to have some sort of a double-whammy to get your audience there. Niches are going to remain niches, but this mass broadcasting thing is clearly in trouble.”

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Longtime TV writer and showrunner Rene Balcer may have been at the helm of one of the smallscreen’s more lucrative spinoffs in “Law and Order: Criminal Intent,” but it’s hard to think of any obvious precedent for his latest venture — as a songwriter for North Carolina bluesmen, in collaboration with a Chinese artist and MacArthur “genius” grant recipient.

Balcer’s debut as a blues lyricist can be heard at the Virginia Museum of Fine Art, accompanying Chinese artist Xu Bing’s exhibit “Tobacco Project Virginia.” An admirer of Xu’s, Balcer composed a poem, “Backbone,” to be incorporated into his art; the poem, a tribute to the women who worked on tobacco plantations, is based entirely on phrases taken from stencils used by 19th century growers to trademark their wares.

“For an exhibit that takes place in Virginia, the blues somehow has to be a part of it,” Balcer recalled.

Balcer and songwriter Michael Sackler-Berner (who contributed music to the “Law and Order” franchise) sought for blues artists to interpret the poem into song, even reaching out to Robert Johnson contemporary David “Honeyboy” Edwards, who died last month. They eventually found a pair of North Carolina veterans, vocalist Captain Luke and guitarist Big Ron Hunter, both of whom coincidentally had childhood experiences on tobacco farms.

“The words basically come from 19th century Virginia, so it felt authentic. I certainly don’t think I’m going to be writing blues songs about waking up this morning and finding out my Maserati got repossessed,” he laughed. “But this one just felt appropriate.”