Page 132 - The Master Handbook Of Acoustics
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SPEECH, MUSIC, AND NOISE
music areas, both the dynamic range and the frequency range would be
greater to accommodate the short-term transients that contribute little
to the overall average, but are still of great importance.
Noise
The word “signal” implies that information is being conveyed. How can
noise be considered an information carrier? An enthusiastic “Bronx
cheer” raspberry conveys considerable information about the perpetra-
tor’s attitude toward someone or something. Noise is the basic part of
such a communication, modulated in just the right way. Interrupting
noise to form dots and dashes is another way to shape noise into com-
munication. We will also see how a decaying band of noise can give
information on the acoustical quality of a room. There are types of noise
that are undesirable. Sometimes it is difficult to tell whether it is the
120
100 170–4,000 Hz
Sound - pressure level, dB 80 42 dB Speech
60
40
20
0
20 50 100 300 500 1 k 3 k 5 k 10 k 20 k
Frequency - Hz
FIGURE 5-13
The portion of the auditory region utilized for typical speech sounds.
