When an art based on form, such as music, is married to one based on content, such as drama, the two must work together to make a point. Often, this requires one or the other to give up some of its autonomy for the sake of cohesion. Several current records show how delicate the balance between music and storyline must be.

"HAIR," which caught the spirit of the '60s and died when that spirit evaporated, is back in an expanded version. Milos Forman's film has given us a new "Hair" album, this one a two-record soundtrack. Though the movie's dramatic action still takes place in the late '60s, the music we hear is distinctly late '70s in character.This isn't particularly detrimental, but it is somewhat contradictory.

For "Hair" to be translated to the screen, some compromises in attitude had to be made, and those compromises necessarily included the music.

"Aquarius," "Hair's" anthem and a huge hit for the Fifth Dimension way back when, now begins like something from Pablo Cruise, and is disco-flavored just enough to make it "contemporary." "Good Morning Starshine" (Oliver's only hit, trivia fans) is fuller and smoother, and "Where Do I Go" - possibly the most moving song in the original show - is given a heavy dose of bass and loses some of its pathos.

"Easy to Be Hard," though, is superbly rendered by Cheryl Barnes and outpoints both the original and the Top Forty smash by Three Dog Night. Galt MacDermot's orchestrations here, and throughout the album, are tasteful and effective, but certainly slicker than anything in the earlier stage presentation of "America's tribal love-rock musical."

This "Hair" album offers even more historically than musically - it provides perspective. Here is "flower power" more than a decade later - put through the production machine to emerge smooth and clean. The show's events and words represent our more innocent past, but the accompanying music is pure present. That contradiction is both interesting and a bit startling.

PRODUCER and choreographer Michael Bennett has taken the opposite approach. The stark immediacy of his last show, "A Chorus Line," has given way to a more traditional Broadway musical form in "Ballroom," a lavishly produced musical dealing with the problems of middle age that never found its audience and recently closed. What survives is an original-cast album that, musically, is a more sedate and less syncopated "Promises, Promises" - flowing ballads, big production instrumentals and pleasing vocal combinations.

"Ballroom" was the kind of musical that your elderly aunt would describe with the comment, "Now that was a show" - but one that younger theatergoers might write off as too old-fashioned. Judging from the album, though, "Ballroom" had a lot going for it: story, emotion, fluidity. Maybe shows like "Ballroom" seem too schmaltzy today. Too bad, because the score for "Ballroom" (music by Billy Goldenberg, lyrics by Alan and Marilyn Bergman) occasionally inspires enough feeling to justify the schmaltz.

SCHMALTZ can sometimes be manifested in nostalgia, but the nostalgia of "Ain't Misbehavin'" is pure energy.

The Tony Award-winning revue, which will open in Washington's Warner Theater in early June, is a tribute to Fats Waller, and its cast recording took this year's musical theater Grammy.

The brilliance of the album is most obvious in the way it captures the feel of Waller's times: the 1920s, '30s and '40s, in Harlem. Waller was a composer, musician, comedian and all-round "character," and "Ain't Misbehavin" reflects his personality and his environment in musical terms.

The credit for that must be equally divided between the excellent company of singer and musicians (which includes veteran jazz pianist Hank Jones) and record producer Thomas Z. Shepard. Shepard, who is a vice president of RCA Red Seal and has eight other Grammies to his credit, deftly alternates tempo for subtle changes in mood and even throws in some snippets of the real Fats Waller.

Though much of the stage presentation involves dance, songs like "Ain't Nobody's Biz-ness If I Do" (Waller's first recorded song, circa 1922), "Honeysuckle Rose" and "Cash for Your Trash" are done in a way that lets the compositions stand totally on their own. Here is a perfectly balanced production - the show and the album work both collectively and independently.

THE soundtrack to "The Warriors" also works independently. It's the movie that many people feel doesn't hold up. However, despite some pretty savage reviews, many film critics have pointed out the movie's choreographed fight scenes and ballet-like action.

The album reflects the story's milieu, projecting a street-tough but graceful musical image. Barry DeVorzon's "Theme From the Warriors" (the single) is a near carbon copy of Giorgio Moroder's "Theme From Midnight Express," but the rest of the record is first-rate.

Kenny Vance and Ismael Miranda do a semi-salsa "In Havana," and Arnold McCuller adequately covers Holland/Dozier/Holland's warhorse "Nowhere to Run." Joe Walsh sounds downright rugged during his "In the City," and the instrumental "You're Movin' Too Slow" is aided by the guitar work of Elliot Randal and Jeff Layton.

The highlights, though, are Mandrill's change of pace, "Echoes in My Mind," Genya Ravan's raw "Love is a Fire" and Desmond Child and Rouge's Springsteen-like "Last of an Ancient Breed."

The movie has been responsible for some beatings in several neighborhoods. Maybe audiences should listen to the record - the musical energy is one beating where no one gets hurt. CAPTION: Picture, LAURIE BEECHMAN, ELLEN FOLEY AND DEBI DYE IN A SCENE FROM THE MOVIE VERSION OF "HAIR."