From The Storm of Style:

What Mozart might have done next [if he hadn’t died young] is no one’s guess. The pieces that emerged from the suddenly productive year 1791 — The Magic Flute, the ultimate Leopoldian synthesis of high and low; La Clemenza di Tito, a robust revival of the aging art of opera seria; the silken lyricism of the Clarinet Concerto; the Requiem, at once cerebral and raw — form a garden of forking paths. Mozart was still a young man, discovering what he could do. In the unimaginable alternate universe in which he lived to the age of seventy, an anniversary-year essay might have contained a sentence such as this: “Opera houses focus on the great works of Mozart’s maturity — The Tempest, Hamlet, the two-part Faust — but it would be a good thing if we occasionally heard that flawed yet lively work of his youth, Don Giovanni.”

And, on a totally different topic, from Listen to This:

Picture music as a map, and musical genres as continents— classical music as Europe, jazz as America, rock as Asia. Each genre has its distinct culture of playing and listening. Between the genres are the cold oceans of taste, which can be cruel to musicians who try to cross over. There are always brave souls willing to make the attempt: Aretha Franklin sings “Nessun dorma” at the Grammys; Paul McCartney writes a symphony; violinists perform on British TV in punk regalia or lingerie. Such exploits get the kind of giddy attention that used to greet early aeronautical feats like Charles Lindbergh’s solo flight and the maiden voyage of the Hindenburg. There is another route between genres.

It’s the avant-garde path— a kind of icy Northern Passage that you can traverse on foot. Practitioners of free jazz, underground rock, and avant-garde classical music are, in fact, closer to one another than they are to their less radical colleagues. Listeners, too, can make unexpected connections in this territory. As I discovered in my college years, it is easy to go from the orchestral hurly-burly of Xenakis and Penderecki to the free-jazz piano of Cecil Taylor and the dissonant rock of Sonic Youth. For lack of a better term, call it the art of noise.

“Noise” is a tricky word that quickly slides into the pejorative. Often, it’s the word we use to describe a new kind of music that we don’t understand. Variations on the put-down “That’s just noise” were heard at the premiere of Stravinsky’s Rite of Spring, during Dylan’s first tours with a band, and on street corners when kids started blasting rap. But “noise” can also accurately describe an acoustical phenomenon, and it needn’t be negative. Human ears are attracted to certain euphonious chords based on the overtone series; when musicians pile on too many extraneous tones, the ear “maxes out.” This is the reason that free jazz, experimental rock, and experimental classical music seem to be speaking the same language: from the perspective of the panicking ear, they are. It’s a question not of volume but of density. There is, however, pleasure to be had in the kind of harmonic density that shatters into noise. The pleasure comes in the control of chaos, in the movement back and forth across the border of what is comprehensible.