CLASSICAL DISCOVERIES: Marvin Rosen, host of the “Classical Discoveries” program, in the WPRB studios at Princeton University.

“You know, in our world today, all over our world, there is just so much incredible talent,” Marvin Rosen says as he leans back in his seat contentedly, wire-rimmed glasses on his nose, a nest of curly brown hair atop his head. “I could never air everything that I would want to air.” 

Mr. Rosen is the host of “Classical Discoveries” on WPRB (103.3 FM), which celebrates its 20th year on the air this month. The well-loved radio station, housed on the campus of Princeton University, is student-managed, and while most of the DJs are students, some, like Mr. Rosen, are community members.

WPRB is known for its eclectic programming, and Mr. Rosen explains that, for DJs, “the freedom is priceless.” When he started doing his show in 1997, he mostly stuck to the so-called “warhorses”— classical pieces most listeners already know and love: Dvorák’s New World Symphony, Bach’s Brandenburg Concertos, etc. But he quickly realized that when listeners called in, it was usually about the pieces they’d never heard before, so he shifted his focus to lesser-known composers and their works. Now, “Classical Discoveries” emphasizes the very new (living composers), the very old (Baroque and earlier), and the geographically far-flung (work from eastern Europe and elsewhere). Each March, the show features a similar repertoire, but exclusively by women composers. Mr. Rosen is a faculty member at Westminster Conservatory. His colleague, percussionist Mika Godbole, describes his radio programming as “obscure but beautiful and compelling.”

Mr. Rosen’s show implicitly raises questions about what we mean when we speak about “classical” music. Is it a period of music — a cohort of composers wedged between the Baroque and Romantic eras? Does it necessarily come from “the West”? In what settings is it performed, and on what instruments? Mr. Rosen readily acknowledges that, as a label, “classical,” comes with the baggage of listeners’ preconceptions. “Why don’t we call it concert music?” he suggests. Still, for the sake of the show he sticks with the term because, “you want to try to expand the people who listen to classical music.” The name is a way for him to get people in the door.

A similar instinct to not scare off listeners informs the way Mr. Rosen puts together his playlists. “I never wing it,” he avers. His weekly show starts on Wednesday mornings at 5:30, and given the hour, he says he likes to “start a little slow.” He structures each show around several major works, and he is careful to ease his audience into the more challenging programming, saving any electronic or avant-garde works for the end of the show. “But it’s always stuff that’s listenable,” he assures me.

Throughout our conversation, Mr. Rosen emphasizes that his show is a “pair effort” made possible with the help of his wife Beata Rzeszódko-Rosen — whom he met, appropriately, because of their shared love of the music of the 20th-century American composer Alan Hovhaness. She runs Mr. Rosen’s website and publicizes his shows on social media. She is up with him at 3:30 a.m. on Wednesdays, making sure he gets to the studio on time, a sack of CDs in hand. Zena Kesselman, a WPRB student DJ and former station manager, agrees that it really is Team Rosen that puts on “Classical Discoveries,” remarking that Beata often comes to all-station meetings with Marvin and keeps station members on their toes with tough questions.

“Classical Discoveries” will celebrate its 20th anniversary on May 29. Mr. Rosen will share listener comments and some of his own recollections of his favorite broadcasts, and he plans to revisit some of the first pieces he played on air.

The discovery continues.

Marvin Rosen’s show “Classical Discoveries” airs Wednesdays 5:30-11 a.m. on WPRB (103.3 FM) and streams online at wprb.com.