The music of Mexico is the cry of a land whipsawed by change

Julio Estrada flips on the stereo among the packing crates in his Mexico City home, and a lone violin cries in a strange new musical language. It tells a tale of human suffering and desire.

Mr. Estrada - a slender man with dark, troubled eyes - is a Mexican composer. But he does not compose in Mexico.

''This country has a huge history of culture, one of the most vivid in the world,'' Estrada argues passionately. But he asserts that Mexican music has been reduced to ''depending on outside musicians'' to set its compositional standards. Now, he says, ''We need to create our own dreams.''

Right now, however, this country heaves and pulls under a burden that leaves little room for dreaming.

In the music of Mexican composers, you can hear the cry of a land whipsawed by modern economic travail and ancient social wrongs. And in the music world they inhabit, you can see a microcosm of almost everything that has gone wrong with the life of this diverse country.

Julio Estrada, for instance, composes and teaches in the United States, as he cannot find the technology in financially ravaged Mexico to develop his advanced theories - and because, he says, such ideas are not well received by Mexico's powerful musical oligarchy.

There are those who would dispute Estrada's view of himself as an artist-in-forced-exile. ''Julio likes to see himself as an exile,'' says Mario Lavista, a fellow composer. But few would disagree that Mexico no longer charts the independent musical course it once followed.

As long ago as the 1910 post-Mexican Revolution era, composer Carlos Chavez forged a Mexican idiom and a musical life to nourish it. The onrushing change that poured out of the revolution bore Chavez - as it did the poets, thinkers, and painters of Mexico - pell-mell into the heart of the nation's confrontation with the future. Chavez, and such contemporaries as Silvestre Revueltas, helped create a Mexican appetite for contemporary music that survives to this day.

By third-world standards, Mexico still has a thriving symphonic and chamber-music life. But there is little to sing about in the outlook for the country's musical culture. The reason: The compositional mainstream here has been both supported and strangled by what many feel is a hidebound cultural bureaucracy.

With the nationalization of the banks in September of 1982, the last independent source of funding for cultural enterprises disappeared. Mexican composers and musicians now work for the state, or they work for no one.

Until the collapse of world oil prices in '82, the flood of Mexican oil expectations fueled a boom in orchestra building, helped in large part by former President Jose Lopez Portillo's wife, Carmen Romano. But there was more enthusiasm than planning behind this expansion.

''At one point, we had more orchestras than musicians,'' quips Manuel Enriquez, the country's leading composer. ''We had to bring in European players. And we had to bring up students from the schools before they were ready.''

Composers here despair of raising the level of performance in these ensembles. ''We are a poor country now,'' Mario Lavista laments.

Alberto Alba, the round-faced, solicitous director of Mexico's National Conservatory, sits in his run-down office one afternoon and explains matter-of-factly that, because of the country's economic crisis, Mexico's largest music school cannot afford instruments for its pupils.

One of the only solutions, he says, is to ask visiting US high school bands to sell their instruments (at reduced prices) when they return home.

More troubling to composers than the lack of instruments is the fact that they cannot invite guest soloists, let alone major orchestras, to perform here.

To the country that once hosted Stravinsky and Bartok, this prohibition - decreed by the government and occasioned by the weakened peso - seems devastating. By long-established tradition, visiting musicians don't simply play concerts: They often teach classes and listen to local music, and they sometimes stay up all night talking with local composers and conductors.

Today, a small band of composers, headed by Enriquez, is struggling to keep the currents flowing. They all left Mexico to study in New York and Europe. Now they are back here, toiling at their craft.

With Enriquez, this craft takes on a fierceness and beauty reminiscent of the country's savage history. A student of Persichetti, William Schuman, and others at Juilliard in New York, Enriquez strives for images that German, American, English, and Japanese composers hanker after. ''I am very fond of the new trends and colors,'' he says, as he plays a tape of his works for a visiting reporter. Although neither he nor any other Mexican composer has come near Chavez's international stature, Enriquez is widely credited with carving out his own national-international persona.

But Manuel Enriquez is not the problem. The problem, according to most observers, is: Who comes after him? Right now, nobody is offering any answers.

Musical trends around the world are charging ahead in numerous directions. New technology has become enormously important in the development of theory. And these trends and this technology are generally out of the reach of young Mexican composers. Many of them are hard pressed to get the books containing new theory.

''This is a hard time,'' comments Gerard Behague, author of ''Music in Latin America'' and chairman of the music department of the University of Texas at Austin. ''Composers will not be as productive as in better times.

''The select few will have the limelight,'' he says, but he worries about ''the younger, potentially talented'' crop of composers whose place in the sun may not show up for a long time . . . ''maybe never.''

History has a way of defying the best analysis.

Carlos Chavez grew up as a talent during the most violent, most difficult period in Mexico's national life. And no one is writing off the hope that, in a country that has a way of coming up with the dramatic, impossible, and beautiful , a Chavez is coming of age somewhere.

''I think they are going through a hard time, not just economically, but in terms of finding their own identity,'' Peter Schoenbach muses. ''But I have a lot of hope for Mexico. I think they have a lot to tell us.''