It was the loudness of the music that upset the listeners and ''drove more than 100 of them out of the hall,'' the reviewer wrote. ''Glass must want it thatway, but the amplification level was near the threshold of pain, and only by stopping the ears could one hear the movement of the wind instruments under the jangling roar from the two harmoniums.''

Glass laughed when he was reminded of that long ago event.

''Yeah, I remember that,'' the composer said in a telephone interview last week. ''It was one of the first times that ever happened to us. Even back then most of the people who came to our concerts knew who we were, and they just expected it to be loud. We were surprised at what happened in St. Louis. I guess the St. Louis audience was surprised, too. Maybe they thought we were a string quartet or something.''

The listeners who hear Glass' eight-member group perform at Powell Hall on Oct. 25 probably won't be nearly as surprised as were their counterparts at the Art Museum thirteen years ago.

After all, when Glass made his St. Louis debut in 1972 he was a fairly obscure representative of contemporary music's avant-garde fringe, an impressively pedigreed Juilliard graduate who in the mid-1960s abandoned the various academically fashionable styles in favor of an austere and as yet untried new aesthetic called Minimalism, a still-struggling artist who had to supplement his meager performance revenue by driving a cab or working as a plumber.

TODAY, at age 48, Glass is something of a superstar.

In an era in which few new operas are ever given a second production, Glass has seen numerous stagings both in Europe and America of all four of the operas he's written since 1976, and his current project - a treatment of Doris Lessing's novel ''The Making of the Representative for Planet 8'' - is already scheduled for performance in Amsterdam in the fall of 1986 and in Houston the following year. Three of Glass' operas (the 1976 ''Einstein on the Beach,'' the 1980 ''Satyagraha'' and the 1982 ''The Photographer'') have been recorded on the CBS Masterworks label. Other of his albums - most notably the 1977 ''North Star,'' on Virgin International, and the 1982 ''Glassworks,'' on CBS - have had as much success with pop music fans as they have with the classical and avant-garde crowd. At least in part because of Glass' soundtrack, Godfrey Reggio's film ''Koyaanisqatsi'' was a sensation at the 1982 New York Film Festival; at least in part for the same reason, Paul Schrader's new cinematic biography of the Japanese writer Mishima Yukio is drawing large crowds wherever it's screened. Glass was one of only a handful of American composers commissioned to provide music for the opening and closing ceremonies of last year's Olympics. A few months ago the magazine Musical America named him ''Musician of the Year.''

Except for excerpts from Glass' most recent theater pieces - ''Akhnaten'' and ''The CIVIL WarS,'' both from 1984 - all of the music the ensemble will present at Powell Hall is available on disc. The material has been given so much air-play that it's hard to imagine that anyone who attends the concert will not already have sampled the spinning melodic figures, pulsing rhythms and glittery tone colors that are Glass' compositional trademarks. It's hard to imagine, too, that any listeners even remotely familiar with Glass' music are not also at least somewhat aware of his reputation for high volume concert performances.

''We play it loud because that's the way we like to do it,'' Glass said. ''That's the main reason, but there are aesthetic reasons as well, and they're a direct result of the kind of music I was writing prior to 1975.

''I REMEMBER we played 'Music With Changing Parts' in St. Louis. When you listen to a piece like that, which is very tonal and based on repetitive structures, you can hear all kinds of psycho-acoustic phenomena - overtones, undertones and so on - but only when the music is loud. A high decibel level puts a sort of patina on it. It triggers the resonant frequencies of the room in which it's being played, and those vibrations actually become a part of the music.

''In the late '60s and early '70s we used inexpensiveelectric organs because that's all we could afford, and we turned up the volume in order to enhance the acoustical effect. My music has changed a great deal since then, and, actually, most of what I've written lately has been relatively quiet music for singers and unamplified orchestras. But in the old days the high volume was such a part of the ensemble's collective style that I decided to keep it. Now we work with very sophisticated electronic music synthesizers - we'll have about eight of them on stage with us in St. Louis - and so the acoustical effects are richer than ever. How loud is it? Well, a full orchestra playing as loud as it can doesn't even come close to where we are most of the time, but we're not as loud as most rock bands.''

Glass was born in 1937 in Baltimore. His first instrument was the flute, which he studied as a teenager at his hometown's Peabody Conservatory. After earning a bachelor's degree at the University of Chicago at age 19 he entered the master's program at New York's Juilliard School of Music, where his principal composition teachers were Vincent Persichetti and William Bergsma. Upon graduating from Juilliard he won a Ford Foundation fellowship that placed him for a year in the Pittsburgh Public School System as composer-in-residence. Having had his fill of writing marches and overtures for high school bands, in 1964 Glass decided to further his education even more - he won a Fulbright Scholarship and, like so many American composers before him, he moved to Paris to study with Nadia Boulanger.

THE RELATIONSHIP with Boulanger lasted two years, during which time most of the new music Glass heard was of the stringent, ultra-intellectual sort served up by Pierre Boulez and his colleagues. Boulanger's traditional mode of teaching and the preponderance of 12-tone serial music in the Paris concert halls weighed heavily on Glass. Just when he felt most like rebelling - in the spring of 1965 - he landed a job as transcriber of music the Indian sitar player Ravi Shankar had composed for Conrad Rooks' film ''Chappaqua.'' Glass then knew very little about Indian music, but in two of its most obvious features - static harmony and irregular rhythms - he found what he regarded as the antidote to what he felt were stifling classes with Boulanger.

When he returned to the United States in 1967 Glass already had in hand several compositions in which a single melodic kernel - usually a simple figure in steady eighth notes, made up of only two or three different pitches - was repeated many times. After a while the music would change slightly - while volume, sound-color, tempo and pitch content would remain precisely the same, the germinal melody would be extended, say, from seven to nine notes. This new figure would be repeated 20 or 30 times, and then the melodic cell would expand again. As the process continued other pitches might be added to the mix, or the melodic figure might be contracted in length, or the first line of music might be joined by another in parallel or contrary motion;always, though, the subtle changes involved mostly rhythm, and always the other elements of the music held fast. The music featured no ''development'' of materials in the traditional sense of the term, nor was there any movement toward climax or denouement. Typically a piece just stopped abruptly, but only after its monochromatic filigrees had droned on long enough to cast a near-hypnotic spell over its listeners.

''I THINK THE term 'Minimalism' is actually a pretty good word to describe the music I was writing prior to 1975,'' Glass said.

''But it doesn't really apply to the music we'll be playing in St. Louis. The oldest piece on the program is one of the dances from 'Einstein on the Beach.' 'Einstein' was my first theater piece. It dates from 197, and it marks a turning point in my music. Since 'Einstein' my music has grown increasingly more melodic and harmonic; it's become much softer in texture and color, and it's even become much more traditionally structured. The reason for all this happening has to do with the theater.

''All my major projects over the last decade have been in the area of opera, dance or film. Most of them have involved a collaboration of one sort or another, so I've tried to bring in as many different elements as possible. And I discovered I'm very good at working in 'theatrical time' - you know, making music move in a certain definite direction, building up to dramatically significant climaxes, coming up with rhythmic changes that actually have something to do with theatrical situations.

''And I've been working with the voice so much. The singing in 'Einstein' was 'minimal,' I admit. But in 'Satyagraha' and 'Akhnaten,' which use a regular orchestra, the singing is extremely lyrical. And I'm going even further in that direction with this Doris Lessing opera I'm finishing up. In 'Satyagraha' and 'Akhnaten' it wasn't so important that I made the words easily understandable, because they were in Sanskrit or Egyptian or Hebrew. The Lessing opera is in English - that's made me think about the voice in a completely different way, and it's made me think about how we understand language.

Did it make a difference?

Yes, but the effect was not at all the negative one an impenetrable language barrier usually has on the operatic experience.

Glass' 1980 ''Satyagraha,'' to be sure, is an avant-garde opera. It poises on the art form's cutting edge, however, not because of its music, which is in the repetitive, harmonically simple style called Minimalism, but because of the relationship of that music to the dramatic and literary elements. Like the other two works in Glass' operatic trilogy that pays homage to ''men whose visionary ideas radically changed the perceptions of the world around them,'' ''Satyagraha'' has less to do with an historical figure per se than with the concept that makes that figure historically important. It is an opera not so much about a great man as about the power of a great man's thoughts.

The first work in the series was the 1976 ''Einstein on the Beach,'' an iconoclastic theater piece that runs five hours without intermission and whose decidedly non-lyrical music is accompanied mostly by high-decibel electronic organs and synthesizers. The third was the 1984 ''Akhnaten,'' a conventionally scored, conventionally structured and highly lyrical opera named after and based on the life of the Egyptian pharaoh who, according to some scholars, pre-dated Moses in his belief in a single, omnipotent god.

Whereas the general themes of ''Einstein'' and ''Akhnaten'' are science and religion, respectively, ''Satyagraha'' deals with politics. It borrows its title from the civil rights movement Mohandas K. Gandhi launched in South Africa in the early years of this century (''satya'' is the Sanskrit word for ''truth,'' and ''agraha'' is the Sanskrit word for ''strength''). The format and musical materials are similar to those of ''Akhnaten.'' Gandhi is the main character, and the opera's seven episodes are comparable to those depicted in the first part of Richard Attenborough's epic 1982 film biography of Gandhi.

The episodes, however, are not presented in chronological order. Nor are they fitted out with words in any way specific to the characters' actions. The text is scriptural, drawn entirely from the Indian ''bible'' called the Bhagavad-Gita. Although the performers do things on stage that seem more or less realistic, what they sing amounts only to glosses on the situations. Imagine an opera about Jesus whose libretto consisted solely of aphorisms - in Hebrew - from the Old Testament; as is the case with ''Satyagraha,'' the text would in fact be a sub-text, submerged all the deeper by its realization in an ancient, arcane language.

Being privvy to the sub-text, of course, enables one to penetrate more thoroughly into the ''meaning'' of any work of art. One has to wonder, though: How far can one go with hermeneutics before the effort is counter-productive? At what point might knowledge of a sub-text actually interfere with reception of the perfectly clear message that is on the work's surface?

Questions of that sort are not often raised by opera. Most operas, after all, just tell stories, and in most of them the words are significant elements of those stories. Stephen Oliver's ''Beauty and the Beast,'' given its American premiere by Opera Theatre of St. Louis this past spring, veers from the norm in that the characters sometimes take on the role of narrator and speak/sing in the third person. Even in this somewhat experimental work, however, the words bear directly on the action and the music bears directly on the words. In ''Beauty and the Beast'' as in most operas, action, words and music are intimately connected. That's why translations of foreign-language operas - whether sung or printed - are important; if the listener is to respond fully to the music, he must also respond to the words that motivate that music.

But in ''Satyagraha'' the music is not motivated by the words. It is richly expressive music, but only in an abstract sense; indeed, its nuances are as far removed from the content of the text as the text is from the action. The music is melodious but also simple and repetitive; for that reason, it is not, in itself, terribly interesting. But its cumulative effect, like the effect of a litany prayed en masse in a resonant cathedral whose acoustics completely blur the words, is positively overwhelming.

The Chicago Lyric Opera's excellent production of ''Satyagraha'' is directed by David Pountney and designed by Robert Israel, the same team that mounted the world premiere production in Rotterdam seven years ago. With all its bright white costumes and misty, scrim-filtered lighting, it is visually spectacular in a humble, earthy way. It is also fairly straightforward; that's good, for in ''Satyagraha'' it is only by means of the action that the story of Gandhi's heroic work in South Africa can be told.

For the profound and ineffable message of Gandhi's work, the opera-goer must rely on sound alone. The sounds succeed extraordinarily well in getting that message across, in large part because the exotic nature of the text keeps the listener at such a respectful distance.

And with his first reading of the tale, many a composer has had his spirit pervaded with a desire to express that gloom in music.

Indeed, one of the most famous operas never written is the setting that Debussy planned to make of Edgar Allan Poe's ''The Fall of the House of Usher.'' It occupied him off and on from 1908 until his death in 1917, but there is evidence to suggest that as early as 1890, Debussy was contemplating an orchestral work inspired in part by Poe's little masterpiece of horror literature.

Even though he'd made arrangements for a production with the Metropolitan Opera in New York, Debussy never got beyond writing the complete libretto and the musical sketches for the first 20 minutes or so of what was to be a one-act ''House of Usher'' opera about 60 minutes long.

In 1976, the sketches were fleshed out, independently, by Carolyn Abbate and Robert Kyr at Yale University and by the Chilean musicologist Juan Allende-Blin in Germany. The latter version has been recorded (on EMI-Angel 7479212); Debussy's reconstructed music is hardly as intoxicating as that of his 1902 ''Pelleas et Melisande,'' yet its atmosphere is chilling, and its mounting tension is enough to give listeners at least an idea of how the plot's awful climax might have been handled.

In 1904, Florent Schmitt - who, like Debussy, knew Poe's work through the translations into French by Baudelaire and Mallarmé - composed a ''symphonic study'' based on ''The Haunted Palace,'' a 48-line poem contained within the ''House of Usher'' story. Another symphonic piece, this one based on the entirety of ''The Fall of the House of Usher,'' was unveiled by the American composer Edward Burlingame Hill in 1920.

Not counting Debussy's unfinished project, the first operatic treatment of ''The Fall of the House of Usher'' came in 1921, the product of an obscure American composer named Avery Claflin. A second ''Usher'' opera, by Larry Sitsky, was presented in 1965 at the Hobart Festival in Australia and widely broadcast over that country's public television network. And now there's a third, the latest effort by the increasingly prolific American ''minimalist'' composer Philip Glass.

Glass' two-act opera was jointly commissioned by the American Repertory Theatre and the Louisville-based Kentucky Opera. It had its premiere at the ART's home base in Cambridge, Mass., on May 18; the run at Louisville's Macauley Theatre opened on May 31. Richard Foreman directed, and the sets were by Foreman and Nancy Winters. On the night I attended (June 2), the cast included soprano Suzan Hanson as Madeline Usher, tenor William Hite as Roderick Usher and baritone Steven Paul Aiken as Roderick's friend. They have strong, young voices. But Glass insisted that they, as well as the orchestra members, be amplified; while the singing was good, the electronics were unfortunately crude.

''The Fall of the House of Usher'' is a viable opera, although not nearly so memorable - in terms of its music alone - as are Glass' 1980 ''Satyagraha'' or 1984 ''Akhnaten.''

Whereas the typical opera tells a story, with a narrative line that flows more or less continuously from first curtain to last, ''Satyagraha'' and ''Akhnaten'' are somewhat static musical portraits of men whose ideas, Glass says, altered the course of history. Events in the lives of Mohandas Gandhi and the ancient Egyptian pharaoh Akhnaten, respectively, are indeed depicted in these operas. But the events are not presented in chronological order, and the scenes have less to do with the actions of the events than with their underlying thoughts.

''Satyagraha'' is, in effect, a meditation on Gandhi's concept of strength through passive resistance, and ''Akhnaten'' is a meditation on its title character's unprecedented concept of a world governed by a single deity. Glass' scores - soft in texture, and gorgeously lyrical in spite of their harmonic simplicity and highly repetitive structures - serve their causes well. Like the lofty ideas they celebrate, the music after a while takes on a resonance not limited by time or place. ''Satyagraha'' and ''Akhnaten'' transcend the familiar boundaries of opera, and in doing so, they earn places among the most significant music-theater works of our time.

(Glass' first opera, the 1976 ''Einstein on the Beach,'' is also significant, but for different reasons. It, too, is a non-narrative ''portrait'' of a great thinker. Its hard-edged, sonically abrasive music is a holdover from the aggressive style Glass developed in the mid-1960s, however, and the score functions primarily as an accompaniment to the extraordinary stage imagery of designer Robert Wilson.)

''The Fall of the House of Usher,'' in contrast, is very much a story-telling opera.

Its music, of course, has a great deal in common with that of ''Satyagraha'' and ''Akhnaten.'' Aside from sonority (the score calls only for a chamber orchestra made up of string quintet, wind quartet and percussion, guitar and synthesizer), the differences have to do primarily with a slightly expanded harmonic vocabulary that allows for slightly more variety in the shapes of sung melodies.

But the format - a string of arias, recitatives and interludes - is quite traditional. The comparable work in Glass' operatic catalog is not ''Satyagraha'' or ''Akhnaten'' but rather ''The Juniper Tree,'' a yet-to-be-recorded one-act setting of a Brothers Grimm tale that Glass composed in collaboration with Robert Moran in 1985. ''The Juniper Tree,'' like ''The Fall of the House of Usher,'' was first presented by the American Repertory Theatre. And like ''Usher,'' ''The Juniper Tree'' features an easily singable libretto by Arthur Yorinks.

Poe's tale, first published in 1840 in Philadelphia in a periodical called Burton's Gentleman's Magazine, teems with references to music.

The Usher family, the narrator says, had in recent generations developed ''a passionate devotion to the intricacies, perhaps even more than to the orthodox and easily recognizable beauties, of musical science.'' Roderick Usher's ''eyes were tortured by even a faint light,'' he reports, and ''there were but a few peculiar sounds, and these from stringed instruments, which did not inspire him with horror.'' On his guitar, Roderick played ''long, improvised dirges'' that ''will ring forever in my ears. Among other things, I hold painfully in mind a certain singular perversion and amplification of the wild air of the last waltz of von Weber.''

There are also graphic references to non-musical sound.

The door of the basement tomb, for example, ''caused an unusually sharp grating sound as it moved upon its hinges.'' A week after Roderick's sister, Madeline, has been interred, the narrator awakes to hear ''certain low and indefinite sounds which came, through the pauses of the storm, at long intervals, I knew not whence.'' At the story's end, as the narrator attempts to calm Roderick's nerves by reading aloud a medieval romance, he hears first a ''cracking and ripping sound,'' then ''a low and apparently distant, but harsh, protracted and most unusual screaming or grating sound,'' then - just before Madeline pays Roderick and the narrator a final visit - ''a distinct, hollow, metallic and clangorous yet apparently muffled reverberation.''

It's a rich palette of sonic effects that Poe offers to a composer, but Glass - following Debussy's lead - prefers not to take them too literally.

To illustrate Roderick's acute sensitivity to sound, he has the narrator (here given the name of William) present his host with a gift; it's a music box, and its melody - rendered on a glockenspiel - is heard again and again as Roderick moves along on the path toward total madness. At the end of the first act, Roderick indeed picks up a guitar, but no guitar music comes from the pit.

At the beginning of Act II, as Roderick and William seal Madeline in her coffin, the strings, bassoon and horn serve up a wash of creepy dark-colored sonority brightened only occasionally by flashes from the flute and clarinet. In the next scene, William's sleep is disturbed not only by orchestral rumblings but also by thunder claps recorded on tape. In the denouement, where the ''cracking,'' ''screaming'' and ''clangorous'' noises described by Poe have parallels in the story that William is relating to Roderick, Glass makes the point simply with sharp whacks on tom-tom, snare drum and a metal plate.

All things considered, the most haunting sounds come from Madeline. When she's on stage before intermission, her melodic material is not much different from her brother's. After she's been buried alive, her high-flying vocalises have a positively crazed ring to them, and they get all the more spine-chilling the closer she gets to her final appearance. In Foreman's production, her frazzled wig and bloody costume were appropriately ghastly, but the build-up of musical intensity was such that her entrance would have been scary even if she'd looked healthy.

Philip Glass' ''The Fall of the House of Usher'' is not the larger-than-life, epic opera that ''Satyagraha'' or ''Akhnaten'' is. Nor is it an opera whose music lingers long in the mind's ear after the house lights come up. It's just an opera that tells a story.

A music-drama it certainly is, although people who like to be technical would label it a melodrama, because playwright David Henry Hwang's are always spoken - never sung - over composer Philip Glass' almost non-stop accompanying score.

But whether ''1000 Airplanes on the Roof'' really tells a science-fiction tale is arguable. Indeed, a better tag for it - one that allows for all interpretations - might be ''psycho-music-drama.''

The 90-minute show, which premiered just three months ago in Vienna, played to a full house Sunday evening in Washington University's Edison Theatre.

I can't imagine that anyone in the audience - except maybe people who absolutely hate Glass' music yet for some reason decided to attend the performance anyway - was not at least to some extent dazzled by this rich combination of text, music and illusionistic stage imagery by designer Jerome Sirlin. At the same time, I can't imagine that anyone in the crowd was not at least to some extent disturbed by what was being portrayed.

''Airplanes'' doesn't tell a story. Rather, it's a slice-of-life portrait of a person who claims she has been abducted and molested by the crew of an alien spacecraft whose noise was comparable to that of the unlikely fleet mentioned in the work's title. (The pronoun could just as easily be ''he''; on Sunday the nameless character was played by actress Jodi Long, but during the current tour Long is sharing the role with Patrick O'Connell.)

One of her close encounters of the third kind is depicted about halfway through. Her speeches, however, offer not a stitch of evidence that this episode - or an earlier episode she merely describes - in fact happened. What matters is that she thinks it happened, and that her unshakable conviction has obviously upset her mental balance. Voices in her head keep telling her: ''It is better to forget, it is pointless to remember, no one will believe you.'' This, she knows, is sound advice; but she can't forget, and as a result her poor psyche is fairly bursting at the seams.

The 400 or so photographs and drawings that make up Sirlin's contribution to this collaborative effort are projected sometimes on a scrim, sometimes on a three-dimensional construction of progressively smaller, progressively recessed proscenium arches from the center of which a ramp extends downward to the lip of the stage. Often the effect is eerily three-dimensional; the actress, lighted from the wings in a way that cleanly washes the projected images from her face and clothes, can appear to walk up the steps of her apartment building, or to be drawn deep into the interior of the spherical spacecraft, or - in a strictly surrealistic scene - to step lightly from one Manhattan rooftop to another.

It's tempting to say that Hwang's script, too, swings from the realistic to the surrealistic. But that, I think, would deny Hwang credit for the extraordinary thing he's accomplished.

In its first half, before the character becomes hysterical, ''Airplanes'' contains quite a bit of flowery language that has the trappings of great philosophical truths. If you read these bits of wisdom as the maxims of a person who has truly been enlightened as the result of something implanted in her brain by extra-terrestrial beings, you can only conclude that her mentors are as inept at poetry as they are at philosophy. But if you read these lines as the spoutings of someone who is seriously unhinged, then it all makes perfect sense.

To describe it like this in pre-performance publicity might scare audiences away; it's a lot safer, and far more attractive to today's public, to say that ''Airplanes'' is a science-fiction music-drama about aliens and UFOs. My hunch, though, is that ''Airplanes'' is based much more on reality than on fantasy. In any case, it seems that what Hwang has done here is to illustrate in graphic detail the inner workings of a severely paranoid schizophrenic.

The impact of Hwang's ''Airplanes'' text is increased substantially by Glass' music. Now an experienced and expert composer for the theater, Glass knows precisely how to conjure up repetitive chord progressions that vibrate with emotional tension or subside into moments of calm. Indeed, this might be his most dynamic small-scale score to date, and there is no question that its realization on Sunday by seven members of the Philip Glass Ensemble was as forceful as was Jodi Long's painfully credible portrayal of the troubled protagonist.

Philip Glass' ''The Voyage,'' performed at the Metropolitan Opera House in New York and broadcast to radio listeners in more than 200 cities, makes virtually no comment on Columbus' relationship with the people who for centuries had occupied the land he claimed to discover. Depending on one's point of view, for an artist to avoid such a touchy issue might be seen either as an act of cowardice or an act of wisdom. Persons familiar with Glass' operatic output, however, would not attribute motivation one way or the other to the composer's decision. Holding to the pattern he established when he began turning out biographical operas 16 years ago, Glass' latest effort is a work that is not at all about the ''reality'' of its subject.

For Glass and librettist David Henry Hwang, Columbus is not so much a character as a symbol, and what he represents is vastly more interesting than anything he actually did. Indeed, this operatic Columbus never even sets foot on the soil of the New World. In the epilogue he is portrayed on his deathbed, evaluating his career and wondering whether it was all worth the effort. Before that he appears only in the second of the opera's three acts; the setting is the Santa Maria on the final day of the sailing, and the curtain falls just as the first mate shouts that land has been sighted.

What Columbus stands for, in ''The Voyage,'' is a willingness to abandon what is comfortable and exchange it - because it is necessary to exchange it - for something new. This, of course, does not jibe with history, for it is by now well known that Columbus' expedition was propelled more by lust for gold and power than by anything else. Still, in the opera Columbus is a reluctant adventurer, an explorer who steps warily into a dangerous frontier in order to blaze an upward trail for the friends he has left behind. It is only through his determination, expressed in a forceful scene that lasts almost 30 minutes, that Columbus identifies himself as a hero. The tone here is strong, but it is unfortunately watered down by the opera's first and third acts.

Whereas Columbus in Act II is clearly a mythic figure, in Acts I and III - set in the mundane world of science fiction - he is a vague metaphor that goes unspoken. Act I takes place largely on an out-of-control spaceship careening toward Earth at the time when the Ice Age was releasing the first humans from its frozen grip. Aboard the spaceship are refugees from a planet no longer able to sustain life; they hope that Earth will prove hospitable, yet they fear the results of their collision with the planet's inhabitants.

''What will they want from me?'' sings the Commander, a high soprano; ''Will I come someday to mate with wordless grunts in a dark cave of groping? Will I know what to do, where to touch, how to kiss? Will I one day find myself loving the stranger? Yes, I suppose that love and that hate mingle like blood between the sheets when two worlds meet.'' The music builds toward a pounding climax; at its conclusion, the Met's announcer informed the radio audience, the Commander ''with her long blue hair'' is ''surrounded by bare-chested earthlings.'' Act III transpires at the end of the 21st century. Simultaneously, archaeologists in India and Peru discover ''homing'' crystals left behind by the space travelers who crash-landed eons ago; as the crystals are brought together, scientists who are scanning the cosmos for signs of life find that their instruments point the way to the ancient visitors' planet of origin. An expedition is mounted. ''We cast off the Earth and thereby ascend to heaven,'' says its Commander, and the act ends with the crew's sad goodbyes gradually turning into tentative hellos. The epilogue shows Columbus in the year 1506, bitter that his promised rewards were never realized, reminded - by the voice of Queen Isabella - that in the name of God he slaughtered the inhabitants of the New World. Yet with his final breaths Columbus argues that he was in the right. ''If our human voyages are riddled sometimes with horrors, with pride, with vanity, with the mother's milk of cruelty,'' he says, ''yet finall y human evil does not deny the good of knowledge, of light, of revelation.'' He dies, and then he, too, ascends to heaven.

Taken literally in the context of today's political climate, Glass' Columbus just doesn't fly. But the character is not supposed to be taken literally. He is an icon, as are the central figures of Glass' three best-known earlier operas. Glass' first opera, composed when he was an aggressive champion of the musical aesthetic called minimalism, was the seven-hour ''Einstein on the Beach'' of 1976.

Four years later, after his style began to soften, Glass used episodes from the life of Mahatma Gandhi to structure a three-act opera titled ''Satyagraha.'' In 1984, writing in a vein even more lyric and expressive, he produced ''Akhnaten,'' an opera nominally about the Egyptian pharaoh who is credited with inventing the concept of monotheism. But ''Akhnaten'' is not really about Akhnaten, just as ''Satyagraha'' is not really about Gandhi and ''Einstein on the Beach'' is not really about Einstein. Nor are these operas - except in the most general way - about the fields of religion, pacifism and science to which these individuals contributed so much.

Glass has said that the three operas, in spite of their differences in sound and format, were conceived as a trilogy; their unified goal, he said, was to celebrate men who in the face of opposition managed to alter the course of history by the strength of their ideas alone. ''Einstein on the Beach'' is plotless, the others very nearly so. They are designed, it seems, as grand-scale rituals, and they succeed precisely because of their abstraction. In the long run, these operas are about a single aspect of the human spirit; what their characters represent is, in a word, courage. In its slow-paced second act and in its philosophical epilogue, Glass' ''The Voyage'' has enough in common with the earlier operas to suggest that what he had in mind was not a trilogy but a tetralogy.

But the sci-fi acts seem cut from conventional cloth. They are straight-line narratives, with dialogue and action of a fairly normal sort. Instead of using music to trigger emotions that amplify the brilliant core of an idea, they simply tell a story. It's a story worth telling, one whose moral we would do well to heed.

On the day of the premiere, to the tune of a budgeted $100 billion, NASA initiated the largest-ever search for radio signals that might be emanating from the deepest regions of outer space. Quite by coincidence, on the same day scientists working the South Atlantic announced the discovery of yet another hole in the precious ozone layer. In the not-too-distant future, earthlings may find that their lives - like the lives of the space travelers in the opera's Act I - depend upon taking to the heavens.

Radio, an invention without which the scanning of the ether would be impossible, is a wonderful medium for sharing with an entire nation a performance that takes place in only one city. But a disadvantage of experiencing opera via the radio is that one can't see how the work is being interpreted; perhaps in the production by director David Pountney and designer Robert Israel there are visual elements that link the three acts of ''The Voyage'' in a way that the score, for all its consistency of melody and rhythm, does not.