Before video killed the radio star and the Internet killed just about the entire hierarchy of the music industry, people used to depend on radio DJs to introduce them to music they liked. File-sharing and Spotify have changed all that, but vast corners of the musical universe are still invisible to the algorithms of digital networks. On WFMU every Friday, Downtown Soulville shines a light on a particularly beautiful corner of this universe of musical dark matter. The man behind the show, Brooklyn's own Mr. Fine Wine, is a dedicated specialist, crate-digging old soul 45s from record shops and yard sales across the country. Each week, he breaks out rare, lost, and lovely selections from his collection of more than 13,000 45s. To listen to Downtown Soulville is to discover the breadth and depth of a genre most people appreciate only superficially. The show airs live Fridays from 8 p.m. to 9 p.m., but, this being the 21st century, it is available anytime on the website or as a podcast. WFMU (91.1 FM), 201-200-9368, wfmu.org/playlists/SV