Inside 20th-century music

Music at the crossroads. An over-dramatic description? Perhaps, but certainly many music lovers during the 1950s and '60s got the message, loud and clear, that the art music of modern times had its lines and camps distinctly drawn. A time when coeval composers could produce works whose every pitch, dynamic and orchestral detail was numerically predetermined; works which ''happened'' via everything from improvising musicians to random radios switched on; and works for electronic or computer sounds with no ''live'' element at all, has at least some liability for being called confusing, if not a crossroads.

Many feel the conflicts within modern music since World War II have had to do with the antagonism of the cerebral and the passionate, the yangm and the yinm, if you will - the detached versus the expressive. For me, the icing on this two-layered dilemma-cake came when I realized that one well-known iconoclastic composer had presented us with a piano piece consisting of four minutes and thirty-three seconds of silence, while another intellectual scientist-composer achieved the same effect with an electronic tape piece for inaudible frequencies!

All lines dom meet at Earth's pole.

At the other pole, however, there are today a few composers who are happily trying to pull together what they see as the best from modern music's crazy quilt history, and forming some interesting and charming hybrid styles as music's various schools and -isms generally learn peaceful coexistence.

One such composer is Joseph Schwantner, a Chicago native whose highly pezsonal amalgam of several far-flung idioms of today's music has taken him a long way, including the 1979 Pulitzer prize for his orchestral piece Aftertones of Infinitym.

Schwantner's early point of departure was apparently formal, serial-style composing. He is fond of setting up predetermined sound schemes and ''synthetic'' scales which then are deftly woven into the fabric of a piece, such as in the early Diaphonia Intervallumm (1966) or the recent Music of Amberm ( 1981), both chamber works. But alongside this in Schwantner's temperament is the aleatoric (chance). A good example of this is Consortium IVm (''In aeternam''), with its basically ''random'' sounds in spite of the strict cycles or ''loops'' of pitches which go to make it up.

There are now and again hints at tonality in his music, and his use of it follows a current trend to avoid any of its traditional, ''functional'' value. However, the f-minor ending of Music of Amberm, for example, is most poignant and a welcome surprise resolution of the work.

A hallmark of Schwantner's music is the rarefied, otherworldly atmosphere he is rigorous about writing into most of his pieces. Perhaps the ultimate, or pretty close to it, in moody, atmospheric music is his wind ensemble piece . . . and the mountains rising nowherem (1977). There are musical ideas going on, though - formal things like repetition and return; and the moodiness spell is more artfully cast than in many pieces from the '60s that came on the tailwind of Penderecki with a wave of fairly vapid sound effects. Although the listener may feel awash in aural effects, things are also contained here in a reasonably apparent structure.

Schwantner does have a tendency to repeat himself in various ways: in favorite instrumental combinations, timbres, special sonorities, and sometimes in actual phrases and melodies, as with a whole motif that crops up in both Music of Amber and Two Poems of Agueda Pizarro (songs, 1980).

Neither Romantic nor Minimalist, Schwantner has always, in an individual way, qualified as an ''accessible'' composer, especially in his very latest music. But, from the beginnings of his emergence, there was a level of excitement and urgency that, up to then, the chance medium hadn't achieved - nor had the serialism of the period. His music can be looked at as one kind of a rite of passage into the freshness of the ''New Age'' we hear so much about today. One isn't sure whether such emotion, gentle as it is most of the time in his works, is where the hoped-for expressive music of tomorrow ought to be headed. But Schwantner clearly is on the side of modern man's getting in touch with the full range of his feelings, examining and trusting them more. A Joseph Schwantner listening list (on reasonably available record labels):

* Diaphonia Intervallum (chamber work)

* Consortium I (chamber work)

* Consortium III (''Modus Caelestis,''

chamber work)

* Autumn Canticles (piano trio)

* . . . and the mountains rising nowhere

(wind ensemble)

* Aftertones of Infinity (orchestra)