Often overlooked in this age of streaming, downloading and shifting listening preferences, traditional radio continues to remain a very popular source of music for many people. We're not talking about Beats 1 or a more customized Internet service such as Pandora, but good ol' fashioned AM/FM radio. With so many avenues for finding and hearing music, it would make perfect sense that many stations are trying to stay as current as possible when curating their selections, but a new study shows that an unlikely contender is spurring massive growth at local stations around the country: classic hip-hop.

As the New York Times reported, a local Indianapolis station occupying the 93.9 frequency spent years struggling to find a successful format. After bouncing around between mainstream hits, classic rock, novelty stations and others, they decided to try their hand at classic hip-hop, inspired by a Houston channel that months earlier had tripled their audience off of the strength of '90s rap hits. Their trial - a "classic hip-hop holiday weekend" - was so successful that they never looked back. The station, renamed 93.9 the Beat, made its way from 15th in regional station rankings to the top spot in only three weeks. It can take a long time to build up an audience after changing from one format to another, so the results seen by 93.9 are not only surprising but historical, as Tom Taylor, publisher of a popular radio-industry newsletter, told the Indianapolis Business Journal, ‘‘Literally nobody in the Top 50 markets in this country has ever done a format change, then in the next full month shot to No. 1 ... Certainly no station in the last decade has done what [WRWM] has.’’

The article suggests hip-hop is following the same course as early doo-wop and later, rock, taking it's "final step toward respectability" by qualifying as a successful oldies radio format. Whether that argument is valid is a debate for another day, but what is certain is that a sizeable fanbase of listeners aged mid-20s to mid-40s exists that want to hear Golden Era hip-hop. The format appeals across all cultures (at least for 93.9) by simply playing the hits, usually with a "pronounced feel-good" sound and a "subtle West Coast bias" such as Biggie's "Juicy" or Ice Cube's "It Was a Good Day." Shying away from more politically charged or overtly violent records of note, the stations play music that listeners want to enjoy in more lighthearted, social settings.

Also interesting, the station's curators follow a number of "rules" that determine playback, utilizing metadata like region and subgenre.

On Cumulus’s version of the format, you’ll never hear back-to-back-to-back Southern rap hits or a cluster of R & B songs with female vocalists; the Beat will break up a block of tunes by harder artists like Ice Cube or DMX with a Mariah Carey track. ‘‘Without flow, this format is a train wreck,’’ Michaels said as he sifted through the computer’s selections, massaging the playlist. ‘‘It’s me being overly anal. I have my own rules.’’ Among them: Notorious B.I.G. and Tupac should never be played back to back (it might call to mind their deadly feud), and a Biggie song should never be played before or after ‘‘I’ll Be Missing You,’’ the tribute song Puff Daddy recorded after Biggie was killed. Michaels also won’t play Outkast next to Ludacris — it just feels weird.

In a world where most music listeners only seem to care about what was just released or what's coming soon, it's great to see real success being generated off the back of celebrated hits from yesteryear. Despite that feeling of "wow, I'm old" you might currently be experiencing, not only is hip-hop from the early 90s now officially considered "oldies," but is dominating the classification. Next time you're controlling the aux cord at your backyard barbeque, remember to sneak in some Mariah Carey if you're planning on playing any DMX.

[By Brendan Varan. He feels old. Follow him on Twitter.]