Composers today use a wider variety of sounds than ever before, including many

that were once considered undesirable noises. Composer Edgard Varese (1883-1965)

called thus the "liberation of sound...the right to make music with any and all sounds."

Electronic music, for example―made with the aid of computers, synthesizers, and

(5) electronic instruments―may include sounds that in the past would not have been

consdered musical Environmental sounds, such as thunder, and electronically generated

hisses and blips can be recorded, manipulated, and then incorporated into a musical

composition. But composers also draw novel sounds from voices and nonelectronic

instruments. Singers may be asked to scream, laugh, groan, sneeze, or to sing phonetic

(10) sounds rather than words. Wind and string players may lap or scrape their instruments.

A brass or woodwind player may hum while playing, to produce two pitches at once; a

pianist may reach inside the piano to pluck a string and then run a metal blade along it. In

the music of the Western world, the greatest expansion and experimentation have involved

percussion instruments, which outnumber strings and winds in many recent compositions.

(15) Traditional percussion instruments are struck with new types of beaters; and instruments

that used to be couriered unconvennonal in Western music―tom-toms, bongos,

slapsticks, maracas―are widelv used.

In the search for novel sounds, increased use has been made in Western music of

Microtones. Non-Western music typically divides and interval between two pitches more

(20) finely than Western music does, thereby producing a greter number of distinct tones,

or micro tones, within the same interval. Composers such as Krzysztof Pmderecki create

sound that borders on electronic noise through tone clusters―closely spaced tones played

together and heard as a mass, block, or band of sound. The directional aspect of sound has

taken on new importance as well Loudspeakers or groups of instruments may be placed

(25) at opposite ends of the stage, in the balcony, or at the back and sides of the auditorium.

Because standard music notation makes no provision for many of these innovations,

recent music scores may contain graphlike diagrams, new note shapes and symbols, and

novel ways of arranging notation on the page.

What does the passage mainly discuss？

A．The use of nontraditional sounds in contemporary music

B．How sounds are produced electronically

C．How standard musical notation has beer, adapted for nontraditional sounds

D．Several composers who have experimented with the electronic production of sound