Music essentially has two dimensions: the horizontal--melody--and the vertical--harmony. But this ignores the most fascinating aspect of music: rhythm. It is rhythm that gives music movement in time. In great music, rhythm articulates and defines both melody and harmony and vice versa (if you can have a vice versa going in three directions). I can think of only one piece that structures itself almost entirely in terms of rhythm: that radical piece by Steve Reich, Drumming. Let's see if we can find a clip of it:
No very good versions... in any case, by developing some new concepts of rhythm, Steve Reich manages to structure a long piece largely with rhythmic resources alone. Quite a tour de force. But not one that can be used over and over. He takes two approaches. One is to slowly fill in the measure, starting with a beat that is not the downbeat. The effect, when the downbeat finally arrives, is striking. At this point he has two or more players duplicating the same pattern. By moving one, slowly, a small unit away, he thoroughly saturates the space. He then does similar things with different instruments before combining them all.
But, this piece aside, what is really needed is a structure that uses melody, harmony and rhythm in a coordinated way. Since the dissolution of tonality, this has been extraordinarily difficult. The problem of atonal (or pan-tonal, if you like) music is that it creates a dissonant, static harmonic structure. And the real problem is not the dissonance, it is the stasis. Most music has had some degree of dissonance for nearly the last thousand years. No, the problem is, that if there is no harmonic center, and therefore other harmonies that are in tension with that center, there can be no harmonic movement. One of the important goals of Bach's Well-Tempered Clavier was to demonstrate the possibility of using any note as the harmonic center. This proved to be massively useful up until the early 20th century. The atonal works by Schoenberg and others create a constellation of tones, none more important than any other--and that is precisely the problem. The use of counterpoint, as in tone-rows and their inversions and cancrizans, does not compensate for the loss of harmony any more than the use of harmony would compensate for the loss of counterpoint.
So, for composers in the late 20th century and early 21st century, harmony has been a problem. We seem to want to re-discover harmony, but it is not so easy! Some composers who have returned to harmony, even when they use consonant chords, seem to be caught in stasis. The harmonic drama that Beethoven, for example, was capable of, we seem to have lost the sense of. Here is an example, also from Steve Reich:
Take away the rhythm and harmonically, there is not a lot of movement. Here is what we have lost:
Now, of course we can't go back to that, but we might ask ourselves what is inextricably part of that moment in music history and what might be more universal? Here is something written in 1950:
That is pretty interesting, but some people would say that it is merely derivative. We can't ask Shostakovich what he is doing because, apart from being not with us any longer, he always denied knowing anything about music theory. Heh. Here is another example, dating from 1977-78:
It takes 110 measures to get to the sub-dominant, so again there is the problem of stasis. We have a tremendous amount of shivery, fluttery rhythmic activity, but that is not harmonic activity. Plus, correct me if I am wrong, but I don't see a lot of Phrygian here.
I'm working on this myself, obviously! I don't want to duplicate music of the past, but at the same time, I want to find a way of creating harmonic organization AND harmonic movement, energy. I don't have anything against using some things from the past to do this. This composer seems to have made some progress:
But I think it will be a while before we can recover the subtlety and dynamicism that harmony was capable of between, say, 1600 and 1900--the so-called "common practice" period.