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
Line of computers, synthesizers, and electronic instruments—may include sounds that in the past would not
(5) have been considered 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 sounds rather than words. Wind and string players
may lap or scrape their instruments.
(10) 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 Lt. 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. Traditional percussion instruments
are struck with new types of beaters; and instruments that used to be couriered unconvennonal in
(15) Western music — tom-toms, bongos, slapsticks, maracas — are widely 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 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
(20) 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 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 graph like diagrams, new note shapes and symbols, and novel ways of arranging notation
(25) on the page.
What does the passage mainly discuss?