In the past, dance companies traditionally have had one city as a home base; now, two-city companies are starting to pop up here and there. The reasons? According to the old adage, two can live more cheaply than one. Dance companies are coming to realize that an inversion of this principle may be the key to survival in a severely strained economy--one can live more cheaply in two.

The Joffrey's Washington visit, for instance, commences a national tour that will end in mid-July in San Francisco. The company's two-week visit to Los Angeles, however, starting April 30, is special--it will mark the troupe's inaugural season as a "resident" company of the Los Angeles Music Center, and hence, a crossing of the threshold into the Joffrey's second home, its first being New York City. And as time goes by, the company will become more and more "bicoastal."

The Joffrey Ballet isn't the only one in the picture--the thing is taking on the proportions of a trend. The Cincinnati Ballet Company recently announced it was going to stake out a new, second roost in New Orleans; the Hartford and Fort Worth ballets are looking towards a coproduction partnership. And it isn't just ballet companies--New York's Rachel Lampert and Dancers, as one example in the modern-dance realm, is seeking to establish a second home in Little Rock. Strictly speaking, these other instances are "bimunicipal" rather than "bicoastal," but the idea is the same, and so is the motivation.

Robert Joffrey, the 52-year-old founder and artistic director of the Joffrey Ballet, who was in Washington a couple of weeks ago for meetings of the National Council on the Arts, talked about his company's new move and its implications for the future.

"Everyone wants to be wanted," he said, "and the wonderful thing about the Los Angeles Music Center situation is that they want our company as it is, which is one of the reasons I'm so happy and excited about it. They're not asking us to bring 'stars,' or to perform 'Swan Lake.' They know what we are and what we do, and that's what they're after. Our new committee out there has already raised close to the $2 million they've guaranteed us for our first two years under the new arrangement. The thing is, until now, the Music Center has been the one major performing arts center in the country with no dance component--Lincoln Center has the New York City Ballet, and I've always thought of the Kennedy Center as having American Ballet Theatre as its resident troupe. So we're fulfilling a need of theirs, as they will fulfill ours."

Indeed, despite fitful attempts to fill the vacuum, the 18-year-old Music Center has never had a participant dance company to match its offerings in other media, such as the Los Angeles Philharmonic and the center's resident theater and opera groups. For that matter, Los Angeles itself has never managed to support a major dance company in any sustained fashion. The most recent attempt to establish an indigenous classical ballet troupe--the Los Angeles Ballet, founded by former New York City Ballet dancer John Clifford--is of a much smaller dimension than the Joffrey, and was rejected as a possible Center constituent by the task force appointed to choose a resident ballet. ABT was a candidate for a while, but decided on its own that the 3,000-seat Chandler Pavilion at the Center would be uneconomical for its requirements.

Among the nation's large ballet companies, the Joffrey has always had a distinctive identity, and one that perhaps makes it ideally suited to the idea of a West Coast residency. The New York City Ballet is unique in having had George Balanchine as its director and creative force, as well as a permanent stage of its own at the New York State Theater, so its need for touring has been minimal. ABT, like the Joffrey, has never had its own theater and has depended heavily on touring; but unlike the Joffrey, it has had celebrated international names among its dancers and opulent productions of the 19th century ballet war horses like "Giselle" and "Swan Lake" to magnetize its box-office appeal. And among other companies comparable in size and distinction to the Joffrey Ballet--such as the much younger Dance Theatre of Harlem or the considerably older San Francisco Ballet--none has roamed the continent as assiduously as the Joffrey, with its characteristic mixture of youthful dancers and adventurous repertory, combining new ballets with spirited revivals of such 20th-century classics as "The Green Table" and "Parade."

"We've always been a touring company," Joffrey explains. "We've played 49 states, and we've had more engagements in California than in any state, including New York. But the wear and tear on our dancers and our productions has been fearsome. What our bicoastal status will permit us to do is to cut out all those stops we've been making for two or three nights. We'll still tour, but with a second base in Los Angeles, we'll be able to concentrate on six to eight major cities in a given season, rather than 12 or 13, and we'll rotate the cities we go to each year. From Los Angeles itself, we'll be within good reach of San Francisco, Seattle and Portland, which have always been major stops for us, and in the future we hope to add others like San Diego and Santa Barbara."

The company has its studios, its school and its junior troupe, Joffrey II, in New York, where for the time being they'll remain as substantial anchors. And Joffrey says there'll still be extended New York seasons, as well as annual Washington visits. But it's a measure of the extent of the mutual commitment between Joffrey and the Los Angeles Music Center that the initial announcement stated that "the principal offices of the company will move to Los Angeles no later than August, 1984, by which time it is anticipated that the greatest number of performances of the company will be presented in Southern California."

The prospect of a formidable funding base, was, of course, one of the chief lures for the Joffrey troupe, which has had a rocky fiscal time of it in recent years. A precondition of the agreement with the Music Center was the erasure of an accumulated Joffrey deficit of $750,000, and that has been accomplished. The promised $2 million initial two-year subsidy will go a long way towards ensuring stability for the venture in its early stages. After the second year, the Music Center has agreed to subsidize the company on the same basis as it does its other resident organizations.

Joffrey admits the whole operation is a giant gamble, but one the company is both ready and eager to undertake for its potential benefits. Meanwhile, his head is filled with new production plans--"I've got enough projects for 10 years," he says. "Laura Dean will complete the trilogy we originally planned, and that's now been realized in 'Night' and 'Fire,' with a third ballet for us for the fall of '83. William Forsythe will do two new ballets--we hope to introduce the first on our opening night in Los Angeles in April. We've also invited Twyla Tharp to create something for our West Coast residency. Frederick Ashton has given us his Isadora Duncan ballet for Los Angeles. We also want to revive our evening of Kurt Jooss ballets, and we're looking to some of our own company people, like Trinette Singleton and Philip Jerry, who've shown choreographic interest and promise.

"I want to mount Cranko's 'Eugene Onegin' at some point, and I'm determined to have a full-length 'Romeo and Juliet' of our own, too, perhaps for the '84-85 season. We've actually been working as well on a reconstruction of Nijinsky's original 'Le Sacre du Printemps'--I'd love to stage it with the Los Angeles Philharmonic, maybe in 1985.

"As for my longstanding dream of a 'Cinderella' ballet to the great Prokofiev score--when my fairy godmother shows up, we'll have that, too."

The Kennedy Center programs the troupe brings to Washington this week are a typical Joffrey mix--13 ballets by nine choreographers, all of this century. There'll be two Washington premieres--Dean's "Fire," with much-touted sets and costumes by architect Michael Graves, and Gerald Arpino's "Round of Angels," set to the Adagietto from Mahler's Fifth Symphony. There'll also be four revivals--Tudor's "Offenbach in the Underworld," Nijinsky's "L'Apre s-midi d'un Faune," Ashton's "Illuminations," and Joffrey's own "Pas de De'esses"--as well as such Joffrey staples as "Green Table," "Cakewalk," and "Suite Saint-Saens," among others. As ever with Joffrey, there are things on the menu to suit an amazingly broad range of tastes.