On April Fools' night in 1982, Jesse Fax, the husky-throated fixture at WHUR-FM, the area's leading black-owned radio station, took over the night shift and for the next five hours played music by white artists.

"I played Elton John, Jerry Lee Lewis and old stuff by the Rolling Stones. I had a ball playing what I liked. The listeners liked it too. And the next day management started talking about playing more white music," recalls Fax.

That might have been a hardly noticed gimmick at the time. But when the pioneering station for progressive black music quietly began to play more white artists, that signaled the start of a radical change in the music patterns at local stations.

Two years ago, a listener could easily tell the black and white contemporary music stations apart by the music they played. Now at the nine stations playing some variety of hits formats, the music is almost the same. Only the voices of the personalities, the rotation of the selections, the advertisements and community service announcements or what WEZR-FM's Phil Simon calls "stationality" give clues about the roots or identity of the stations.

Consider the New Order:

WDJY, the oldest black music station on the FM side, and WEZR, an adult contemporary station, were the first stations to play "Strut" by Sheena Easton, the Scottish artist who has made her mark with lush ballads and pop rock. WAVA-FM, which changed its format from album-rock to all hits a year ago, raced to play Rebbie Jackson before she caught on, and to be the first to spin the new Kool & the Gang release.

"What About Me," the song by Kenny Rogers and Kim Carnes, who are white, and James Ingram, who is black, was initially played by the black stations.

Back in the summer, the music director at white-oriented WASH heard a black dance song on WHUR by Jocelyn Brown called "Somebody Else's Guy." For two weeks, he played it around the station before he added it to the play list and it became one of the station's most requested songs.

Though Washington's radio marketing has never been as rigidly segregated as other cities', it followed the industry's trend. And, generally, black music has had trouble getting air play on white music stations, except for major black stars or enormous hits. Now more black music is being played on white stations than since the mid-'70s disco mania, and, before that, the 1960s peak of the Motown era.

Smokey Rivers, the program director at WAVA, explains the cycle: "Black music has always fallen in and out of favor, though there has been a subgroup that has always favored the songs. We had the Platters era, then Motown, then that was countered by the British invasion, then in the late 1960s the psychedelic era with Donovan, Cream, Led Zeppelin. Then at the beginning of the 1970s we had a mellowing of attitudes and people got back into rhythm and blues. Then in the mid-1970s another change back to white rock, then disco, then a tremendous backlash among the rock 'n' roll types. Now we are everywhere. And you can't discount the social order, the integration of the public schools and white kids turning on to Midnight Star and black kids turning on to Van Halen."

Because of cultural preferences and marketing segregation, as well as station policy against it, music by white artists was rarely heard on black stations except for the occasional Righteous Brothers song. Now reverse crossover is booming. "There is probably a greater degree of integration on the radio in terms of the music being played than there is in the society at large," says Robert Taylor, general manager at WHUR, which holds an overall third ranking in the market.

And the reasons are many, according to the program directors and deejays. They start with the practical -- playing more current hits appeals to a demographically broader group, and the larger the audience the more attractive a station is to the advertisers.

Donnie Simpson, program director for WKYS-FM, the number two station in the market and an innovator of the urban contemporary format, says, "This black appreciation for white music has been there for a long time. It is just starting to surface in radio, basically because radio is just allowing it to surface. White stations in the past would not play black artists unless they were Michael Jackson or Stevie Wonder. But now they will play Grand Master Melle Mel & the Furious Five."

On the other hand, says Simpson, "The white listening audience, in particular, started to become more aware of black culture, to an extent, with the success of Michael Jackson, with movies that used a lot of black music like 'Beat Street.' "

Bob Hughes, operations manager at WLTT-FM, whose light-rock approach has made it seventh in the market, says the area stations have never had a black- or white-only policy but have responded to the whims of the public. "The charges that we were holding down black artists or white artists are not true. We react to public change in taste and the demand for the product. Most broadcasters are more than willing to be slaves to the public," says Hughes.

Right now the public hunger for all spectrums of music is enormous. Videos, cable television, dance clubs and films such as "Footloose" and "Purple Rain" have made a much larger variety of music available and attractive to both black and white listeners. And some of the music has changed -- Prince borrows from white rock guitarists, Hall & Oates borrow from the blues, and Culture Club mixes reggae and pop.

In 1983, Bill Tanner was new to town and his job as program director and morning man at WASH. He noticed "about the only station attempting to make any kind of compatible black-white presentation was black-oriented WKYS, and it was the runaway leader. It struck me that there was an opportunity to come from a white perspective that played a great deal of black music."

Tanner, who has since left his position at WASH, says he tried to "integrate the music in a logical, predictable manner. You know if you are hearing a white rock record, you will probably hear a more dance- or black-oriented, sound next." Songs on a recent play list by white artists were: "If This Is It," by Huey Lewis & the News; "Cover Me" by Bruce Springsteen; "Missing You" by John Waite. Black songs were "What's Love Got to Do With It" by Tina Turner and "Caribbean Queen" by Billy Ocean. The station ranks 15th.

Among black listeners, choice of a station is much less rigid and political than it was a decade ago. For example, when WHUR first went on the air, almost all of the young, professional, upwardly mobile blacks felt obliged to listen for both musical and political messages.

WHUR now plays one song by a white artist out of every eight. On the list are Madonna, Culture Club (whose bass player is black), Huey Lewis & the News, Hall & Oates (Oates is Chicano) and Sam Harris. The programmers say the station's changes have not prompted a lot of criticism.

"In 1974 or 1975 I played 'Just the Way You Are' by Billy Joel and we got a lot of negative remarks. Now once in a blue moon, you get a complaint," says Fax, the station's program director and cohost of the morning show.

Some stations examine their crossover selection to guarantee a familiar sound for the station. Says Michael Archie, the music librarian, "Springsteen is a little too hard rock. Now, Chicago crosses the color barrier. The white sounds have to have the same sound as the black music. We wouldn't play Def Leppard. But we play Art of Noise."

WRQX-FM, the area's 5th-ranked station, has been a hits station for five years. Popularity and quality, insists music director Mary Taten, are their criteria for air play. "Basically we play whatever is popular. And because of the available music, we do play a lot of rhythm and blues and dance music. We don't consider that we need a black song but we need the best song," she says.

WHUR's Melvin Lindsay, a crossover pioneer and the area's most popular nighttime deejay with a runaway 16.9 share of the audience, has always played Barbra Streisand, Melissa Manchester, Andy Gibb and other white artists: "I go for a certain sound. I don't play something specifically because it's black, or white or anything else. I go with those white artists that deliver some sort of soul. Streisand does it in a different way."

Crossover has one drawback for Fax. "I have a feeling the white artists aren't going to come by black stations and talk. Now you have George Benson and Al Jarreau going by the white stations. They have forgotten their roots because we gave them their start. But we can't stop playing their hits," says Fax. Most recently only the "straight-up rhythm and blues" artists have stopped by WHUR: O'Jays, Grover Washington and the Temptations.

Barry Mayo, one of the leading programmers of black music in the country, says black stations that play white crossover acts do not always get the crossover advertising dollar. At his station, the RKO-owned WRKS, which is the number two station in the New York area, he plays a limited number of white numbers.

"When the stations have the same exact ratings, the black stations lose," he says. "I am trying to educate the advertisers about that." He tells the story of a cookie manufacturer who wanted the age demographic that his station was strongest in but who would not buy time on an ethnic station. "I have to believe that is ignorance. I am black and I have been eating cookies all my life."

However, WHUR and WDJY say their audience shares of the quarterly ratings are starting to pay off in advertising.

The changes at WHUR have netted a 30 percent increase in advertising, says Lennie Chapman, the acting local sales manager. "The general audience can more or less associate with what we are doing. We don't turn off anybody," says Chapman. In general, he says, "white music stations that are playing black music see a quicker increase in sales. In the next year or two it will be easier for the black stations."

Jack Wamsley, the sales manager at WDJY, says his station is experiencing a 10-12 percent increase in revenues over this time last year. The new format with more music by white artists has attracted, said Wamsley, three or four new auto dealers and national accounts, such as Columbia Pictures and Frank Perdue Chicken.

Some experts have feared the new order and competition would take away listener support for the black music stations. Says Gary Byrd, a talk-show host on WLIB-AM in New York, "The risk is that the black music stations will go the route of the dinosaur. Those new white stations have much more money to put on promotions, advertisements. The black station is going to lose unless it follows the new and alternative music." He suggests that black-oriented stations play more reggae, calypso, African, gospel and rap music.

That listener exodus has not happened in Washington.

WKYS, which is owned by NBC, has been number one for seven out of the last 10 rating books. With a recent play list of 88 records featuring 12 white artists, including Chuck Mangione, the Cars, Chicago, Teena Marie and Art of Noise, it reaches nearly 500,000 people a week, the highest of any local station, according to the summer Arbitron Ratings. WHUR, which is owned by Howard University, has gained 40 percent in one measurement of its listeners since it changed music policy.

Ranked 13th in the market, WDJY, formerly WOOK, has gained in the ratings since it changed its format from all-black to 75-80 percent black eight months ago. Out of their top 15 one recent week, 11 were by black artists. But it is not unusual to hear Culture Club followed by Rebbie Jackson and the Bar-Kays after Duran Duran. "The rest is up-tempo, dance, current songs. We look for tempo, but a superstar like Lionel Richie records a lot of ballads, and he can't be ignored," says program director Dan O'Neill. "We are under constant pressure to add slow songs."

In the new order, adds O'Neill, "black recording artists benefit most, more than the radio stations. Chaka Khan went from 1976 to 1983 without having a big top 40 hit. At this moment 'I Feel for You' is being played by all kinds of radio stations."

Since last October WAVA-FM has been playing what its music director calls "the monsters." It is now the 10th-ranked station in the market. The newest trends in crossover are noticeable, says music director Marty Dempsey, because "the rhythm and blues sounds a little better than the rock and pop."

And could it be that the old argument about whose music is better may be heading for retirement?

"I have never heard anyone who programs music say black music is better ," says WHUR's Lindsay. "You hear it from people in the record industry, the promotion people, people whose particular area is to promote black music or the rhythm and blues product. They are the ones who will complain that WHUR is playing the Eurythmics again. 'Give the time to some black artists.' No programmers I know get uptight over it. Every programmer's job should be to please as many people as possible."