Radio stations that feature songs by black artists--R&B, rap, hip-hop and oldies--are now the most popular music stations in the nation's largest cities, according to an industry study released this week.

News/talk continues to be the most listened-to format but--for the first time--black radio moved into the No. 2 spot, eclipsing the longtime runner-up, white-oriented adult contemporary stations. Black radio has risen from sixth to second place over the past decade, largely on the rise of rap and hip-hop and the new Jammin' Oldies format.

The survey was released this week by Airplay Monitor, a publication of Billboard magazine, which tracks the Arbitron ratings of radio stations in the 94 largest U.S. cities.

Nationally, 15.9 percent of listeners favored a talk or news station during the most recent Arbitron survey, which covered July 1 through Sept. 22, according to Airplay Monitor. Black stations, with 13.3 percent, squeaked past adult contemporary stations, with 13.2 percent.

News/talk has been No. 1 since 1994, when it claimed the top spot from adult contemporary.

Radio formats adhere to labels that are, at best, loosely applied. For instance, though rap is as different from Motown R&B as heavy metal is from easy listening, all stations that feature music by black artists are placed under the umbrella "R&B/urban," or black, category.

The umbrella labels are partially maintained by the record companies that sell black artists, to make the genre look as popular as possible, says Robert Unmacht, publisher of M Street Journal, a Nashville radio weekly. Also, they are maintained by industry publications that sell advertising to those companies, adds Unmacht, a veteran industry-watcher.

Were white-oriented stations lumped into one category--say, Top 40, album rock, country and oldies all put together--the audience would far exceed that of black stations. And if the Airplay Monitor survey had included all of the nation's nearly 300 Arbitron-tracked radio markets, not just the largest, the top music format probably would be country. About 35 percent of all stations play country, the largest national plurality.

Nevertheless, the rise in popularity of black radio is legitimate and significant. In the Washington radio market, which has a 38 percent nonwhite listenership, three black stations--WKYS (93.9), WPGC (95.5) and WHUR (96.3)--have dominated the ratings over the last half of this decade. (Adult contemporary is heard locally on WASH [97.1] and WRQX [107.3], among others.)

Nationally, black stations have gained larger chunks of audience over the past two years since introduction of the Jammin' Oldies format, which spread across the country and arrived here in April on WJMO (99.5). Jammin' Oldies stations feature '70s black artists, such as Earth Wind & Fire, Barry White and Kool and the Gang. Unlike black oldies stations--such as WMMJ (102.3), which focuses on Motown tunes and seeks a primarily black audience--Jammin' Oldies stations are targeted at white and Spanish-speaking listeners as well as blacks, and draw them away from adult contemporary stations.

More significant, however, is that black-hit stations--such as WKYS and WPGC, locally--have gained young listeners of all colors, says Unmacht.

"The biggest hits on radio now are from artists that both young African American kids and suburban kids enjoy," says Steve Hegwood, vice president of programming for the Lanham-based Radio One chain, which owns WKYS and WMMJ. "Puff Daddy, Master P, Mary J. Blige, Lil' Kim--all these artists have appeal to both audiences."

Black stations are nationally top-rated among listeners aged 18-34, according to Airplay Monitor. Accordingly, on youth-oriented MTV, two of the five most-played videos in current rotation are by black artists--rapper Will Smith and the R&B girl group Destiny's Child.

Even though WKYS plays black artists and markets itself to area blacks, more than a quarter of its listeners are white and Spanish-speaking, according to Arbitron data, testifying to the music's crossover appeal.

"In addition," Hegwood says, "we know that at least 60 percent of rap music is purchased by suburban kids."

Recordings by black artists are now the nation's top sellers, having surpassed sales of country artists last year.

CAPTION: Black artists as diverse as hip-hop soul singer Mary J. Blige and '70s crooner Barry White are lumped together under the umbrella category "R&B/urban."