This is a tale of two sound tracks. One you've been hearing, whether you wanted to or not. One you won't be hearing, unless you work hard at it.

It's also a story about how contemporary music defines film, either with intelligence or through heartbreak.

The stars? One is Taylor Hackford, a director whose first four films have produced an equal number of hit theme songs. The other is Jerry Goldsmith, an award-winning symphonic composer who has scored more than 100 films only to have his latest effort -- which he thinks is his best -- junked for a rock score.

Taylor Hackford knows the value of a hit single. Two of his recent pictures, "An Officer and a Gentleman" and "Against All Odds," spawned No. 1, Oscar-winning singles (Joe Cocker's "Up Where We Belong" and Phil Collins' "Against All Odds") that certainly helped those films at the box office. After all, the movie-going public and record-buying public in the '80s are essentially the same. (Ironically, Hackford's one musical film, "The Idolmaker," a rock 'n' roll parable based on the rise of Fabian and Frankie Avalon, got no help from radio, which shunned its re-created '50s and early '60s sound track.)

Now Hackford has topped himself. His latest film, "White Nights," has spawned two No. 1 singles, Lionel Richie's "Say You, Say Me" and the Phil Collins/Marilyn Martin duet, "Separate Lives." At one point, they held the No. 1 and No. 3 spots on the Billboard charts.

Hackford's blending of pop hits and film is part of a continuing trend that subtly provides millions of dollars in free advertising for the film industry. But in thinking about how to use music in "White Nights," the director wasn't simply after audio trailers for his film. In fact, helpful as those two hits may be in selling the movie (it has brought in more than $30 million so far), they are not as essential to "White Nights" as the tapes Soviet defector Mikhail Baryshnikov brings back into Russia when a plane crash lands him in Siberia. The music on those tapes -- not exactly what you'd expect your average ballet star to be grooving to -- is by Lou Reed, Chaka Khan, John Hiatt, Robert Plant, Roberta Flack, Nile Rodgers, David Foster and Jenny Burton.

" 'Officer' and 'Odds' were nonmusical films but we used music to exemplify the characters in a contemporary setting," Hackford explains. "With 'White Nights' I was moving towards designing the music to be more than background, more than to score dramatic situations, to actually use it as a catalyst for the characters and the story."

Baryshnikov's collection of pop tunes serves two purposes, according to Hackford. "It's really set up by Hines who also plays a defector, from America being out not just of American but western popular culture for 10 years. He's been shut off from that whole evolution and when Baryshnikov drops out of the sky and has this eclectic group of tapes, it is in fact a discovery for Hines. It's the catalyst by which they dance, but it also allows him to rethink his decision and rediscover his cultural roots."

The two characters, initially at odds with one another, come together as the film goes on and hatch a plot to escape back to freedom. "Since they're constantly under surveillance," Hackford points out, "they use the music as a cover. So ultimately, it was an attempt to use contemporary music in a film and have a much more sophisticated reason for it. It was also fun."

Some critics have pointed out that much of the "White Nights" music is inappropriate for either Baryshnikov or Hines, given the dance styles they represent.

"I am first of all a film maker," Hackford says. "I put music in my films because popular music is important in my life and if I'm making contemporary films, why shouldn't it be important to my characters? Mikhail Baryshnikov does not listen to popular music; the length of his popular taste goes to Sinatra and Streisand. It doesn't fit who he is. But it fits the character, and I think it broadens and gives depth to his character. When they're alone in the dance studio, you expect him to put on Mozart and instead he puts on Lou Reed. I just think the audience is delighted and surprised."

"I make audience films," Hackford insists. "And the concept of this film was not to do a ballet picture, although the film opens with an eight-minute ballet and the music is Bach. The rest of the film was designed to be accessible to a much broader audience than normally watches ballet, and to synthesize these two dancers' work into a more contemporary setting."

If you can't escape the "White Nights" sound track, you're going to have to go to Europe to hear Jerry Goldsmith's sound track for Ridley Scott's upcoming $30 million epic, "Legend."

Goldsmith, the award-winning composer of scores for "Patton," "Chinatown," "Poltergeist," "The Omen" and 100 other films, has had his score dropped in favor of one by a German techno-pop group.

"The picture in the United States is coming out with a score by Tangerine Dream," he reports from Hollywood. "The picture in Europe and the rest of the world is coming out with my score. It came as a total surprise and shock to me."

Apparently, the reasoning at Universal, which owns the North American rights to the film, is that "Legend" -- already delayed more than a year and now scheduled for a late March opening -- can't be sold to America's teens without a sound track that will appeal to them.

"From what I've been told, the picture that will be released in the United States is quite different from that released in Europe," Goldsmith says. "It's been reedited and they've shot some new footage and reconstructed the film for release here. Basically, from what I've been told, to make it more accessible to teen-agers . . . that old story."

Director Scott recently told the Los Angeles Times that the plot had been "tightened up" to emphasize the film's "action-adventure" aspects, and Bert Berman, Universal's vice president of music creative affairs, confirms that the North American version runs at 95 minutes versus 140 for Europe.

"Legend," as Goldsmith describes it, is "a fairy tale in an enchanted forest, with fairies and goblins and unicorns and a sort of Robin Hood and the Beautiful Princess and good and bad. That this dreamy, bucolic setting is suddenly to be scored by a techno-pop group seems sort of strange to me."

Strange, but not unprecedented: Last year's "Ladyhawke" was another medieval period piece sabotaged by a modernistic sound track. Ironically, Goldsmith had been asked to do that sound track but couldn't because he was committed to another project: "Legend."

It should be pointed out that while Tangerine Dream did provide a splendid score for "Sorcerer" (a bust at the box office) and workable incidental music for "Risky Business," the group has not had that much success elsewhere ("Vision Quest," "Thief," "Firestarter"). Knowing this, Universal is hedging its bet: Bryan Ferry will be singing the new theme song.

What makes the "Legend" situation particularly irksome to him, Goldsmith says, is that "it's the best score I've ever done, and people who have heard it have felt it was an outstanding score." Normally, Goldsmith will spend six to 10 weeks on a film score; he spent six months on "Legend," writing songs and dance sequences ahead of time "so they could shoot them. Of course, all that is out now, part of the reediting of the picture."

Meanwhile, Taylor Hackford says, the extensive air play and commercial sales for "Say You, Say Me" and "Separate Lives" are bringing people to this "dance film" who would never come otherwise.

"If you were to say 'Mikhail Baryshnikov' or 'Gregory Hines' to a group of high school students, or even college students, there wouldn't be much interest except the few, like the few in society, that love dance. When you incorporate music that is accessible to these people and say this music is playing in this film and these dancers can do it and make it much more accessible to you, you open up an audience . . . I see a lot of young people going to see 'White Nights,' which a lot of critics said would never happen."

And, Hackford points out, the pop process of "White Nights" is "showing the brilliance of Baryshnikov and Hines to a much larger audience than either one of them has ever had before." This makes the "ballet nuts" angry, he says, "because they would love the world to see 'Giselle.' But the world is not going to. Ballet is an elitist form and it always will be, and its fans are insulted that Baryshnikov is dancing something other than what they consider he should. I expected that parochial view."

"White Nights" has done well at the box office, and the album is Top 25 (even though the Richie song is not on it). There are currently 12 sound track albums on the Billboard Top 150, and 10 sound track singles among the Top 100. With the exception of "Amadeus," they are all pop collections. While traditional symphonic or instrumental sound tracks still come out at a prodigious rate, they are often on small, specialist labels.

Sound track albums have been around for ages, of course, and providing hit themes for just as long. In fact, two of three albums with the longest duration at No. 1 have been sound tracks, albeit film versions of hit musicals ("West Side Story" and "South Pacific," 54 weeks each). From Bill Haley to Elvis Presley's celluloid oeuvre in the '50s, to the Beatles and Barry Sadler in the '60s, to the Bee Gees and John Williams in the '70s, successes have been shared on mutually beneficial terms.

Pop fans learned to be wary after buying a sound track for a hit song and finding it filled out with orchestral themes -- a problem that still occurs, but far less often than it did in the '50s and '60s. In the late '70s, things got out of hand the other way, too, with albums being filled with songs no one could remember hearing in the films. Sometimes, the albums came out and the films didn't (Stevie Wonder's "The Secret Life of Plants"), or just barely made an appearance (Earth, Wind and Fire's "Shining Star").

The twinning of film and rock dates back to "Rock Around the Clock" in 1954, so many of Hollywood's moguls grew up listening to rock and are therefore receptive to its integration into film. But the movie industry has been especially rock-obsessed since "Saturday Night Fever," still the highest grossing album of all time (it's not quite "Thriller," but it is a double album).

As so often happens in Hollywood, however, success led -- very quickly -- to excess.

"I certainly wasn't the first person to use contemporary music in film," Hackford says, "but in recent years I have pioneered the use of contemporary music in nonmusical films. I always do it with an eye to fitting the emotional and dramatic content of my movies -- it has to do that first -- and I have been successful at that. But when you are successful and you get a number one song and people in the Hollywood community see it, they immediately start running around with a big fat checkbook saying 'I want a hit song for my movie, or hit songs, we'll put together a hit sound track album . . . ' "

And that process, Hackford feels, is ultimately self-destructive because "very few of them have musical taste, so they just throw everything into their films. And they pay exorbitant amounts of money to rock groups, who will take the money. It's really poisoning the well, as far as I'm concerned. What ends up happening is that people go to a movie and if it's a sensitive movie, the sound track blows it right out of the water because it doesn't fit.

"It's taking my concept and perverting it," Hackford says. People in Hollywood "don't care if the music fits the film. If it's a hit, they think it will bring people to the theater.

"But you cannot make a hit song with a hit movie. The song has to work and if it doesn't, the audience is going to know it. And likewise, if you have a hit song it isn't going to help a bad movie."

In recent years, fans have been noticing that certain sound tracks feature an awful lot of artists already on the label releasing said sound track (such as A&M's "The Breakfast Club," which helped break Simple Minds with "Don't You Forget About Me"). Nowadays, every record company has a film division and every movie company has its music division. Sometimes the lines blur, as with Universal and MCA, Warner Bros. and Warner Bros.

Of course there are pop artists who have made contributions to the sound track medium in a very traditional, reflective manner -- particularly guitarists Ry Cooder and Mark Knopfler. Cooder's sound tracks for "Alamo Bay" and "Paris, Texas" and Knopfler's for "Local Hero," "Cal" and "Comfort and Joy" are terrific (and didn't sell beans). Still, the pressure to generate hits remains: Even now, lyricists Alan and Marilyn Bergman are scrambling to write a theme song to John Barry's music for "Out of Africa," though the film could be dead at the box office by the time they get it out.

But the dominant trend is the release of ragtag pop collections on the principle that if you throw up enough junk some of will drift back down to earth as gold or platinum. These collections are mostly miss or hit, and seldom have anything to do with the dramatic flow of a film.

Last year's "Vision Quest," for example, produced a number of hits. One came from Journey (there are reports that the group asked for, and got, almost $200,000), but an even bigger one, "Crazy for You," came from Madonna, who also performed in the film. Even her unexpected rise to mega-stardom, however, couldn't help "Vision Quest" -- a surprisingly evocative film about a high school wrestler struggling for self-definition -- which was, in fact, overwhelmed by its sound track.

"You can have a platinum album coming out and the movie dies," says Hackford, "or a great successful movie that has a song associated with it and it never sells, it's a dud. You can't fool the audience."

Still, Hackford sees an insidious trend: Rock groups, especially the bigger groups, are starting to overrecord. "Just two or three extra cuts, but they decide to hold them because some sucker from Hollywood is going to come along and offer them a whole lot of money. The fact is, when you see groups and they say 'I just happen to have an extra cut,' it probably wasn't good enough to go on their album in the first place. So why are they holding it and why are they asking such a huge amount of money for it?"

Hackford prefers to commission his theme ballads, rather than try to match existing material with the emotional content of a film. He chose Collins for "Against All Odds" even though "he was not yet the household name he is now. That was his first number one hit. Like Joe Cocker, I chose him because I felt there was a distinctive quality in his voice. I go after people with signatures in their vocal style, particularly with the ballads that sell films." Stephen Bishop wrote "Against All Odds" for Collins, who went on to have the biggest album of his career.

"For 'White Nights,' " Hackford says, "I wanted a song at the end to exemplify a sort of universal brotherhood. 'Separate Lives' couldn't do it, it was a male-female song. But Lionel Richie is the best at that kind of anthem, so I went after him."

For Jerry Goldsmith, what's done is done. "It's their choice, just like they can get another writer if they want. I would have been more upset if they'd hired another composer and approached it in a symphonic style, but the fact that they went 180 degrees around with Tangerine Dream is sort of a joke to me," he adds, not laughing.

He certainly has no reason to worry about his career. Goldsmith has one of the best reputations in Hollywood and is already working on several new scores ("Link," "Poltergeist II," Franklin Schaffner's "Lionhart" and a commission for the Dallas Symphony). He has gotten lots of sympathetic mail and phone calls from his colleagues in the industry, but insists that "this is hardly of worldly importance. So many people that I work with roll their eyes back like I do at the whole thing . . .

"It's a cyclical thing we go through all the time. If one thing is successful, let's try it again until the next fad comes along. You didn't hear romantic symphonic scores until 'Star Wars,' and then that's what everybody wanted. Then all of a sudden they're selling pop albums like crazy so we'll try that. I don't think that every filmmaker will put up with that. There are certain things this kind of music is appropriate for, other things it's just not. Serious filmmakers are more interested in their story than trying to sell a record."

Adds Hackford: "Films end up, for better or worse, being made from one point of view. The moment that somebody else comes in and says it's no longer your film, you may have designed this score and this film but now we're going to change it and we're going to throw out the score that you as an artist and the composer you collaborated with felt was right for it, that's unconscionable.

"If the studio throws the score out because they want to make something that's a more commercial accommodation, it's probably not going to work. And even if it does, it's not what was intended. I'd never want it done to me."