n. Pitch is the relative frequency of a sound. Loudness or volume is the relative amplitude of the wave
producing a sound.
o. Quality or timbre is that characteristic of a sound which makes it recognizable as a certain kind of sound.
Quality depends on the number of harmonics present and on the relationship between the fundamental and its harmonics.
p. A musical tone is a complex but regular waveform rich in harmonics; noise is a complex but irregular
q. Human speech is characterized by its quality, inflection, and range. Inflection is the small variation in pitch
or loudness which a speaker uses to place emphasis or special meaning on his words.
r. The sounds of the normal speaking voice are at fundamental frequencies between 100 and 300 hertz. The
overtones contained in these sounds extend the voice range of frequencies to approximately 5,000 hertz.
s. The range of fundamental frequencies of the singing voice varies from about 80 hertz to 1,200 hertz; the
overtones reach as high as 10,000 hertz.
t. The range of fundamental frequencies of a symphony orchestra varies from about 16 to 4,000 hertz, with
overtones to 12,000 hertz or higher.
u. Most telephones are limited in frequency response to the range from 200 to 2,700 hertz.
v. Speech transmitted by telephone introduces some distortion, noise, and frequency limitation, causing loss in
intelligibility, naturalness, and quality.
w. The average power contained in speech at a normal conversational level is about 10 microwatts; at the loudest
level it is about 1,000 microwatts; at the weakest level it is 1/10 of a microwatt; at a whisper it is about 1/1,000 of a
microwatt.
x. For any given frequency, the threshold of audibility is the lowest intensity at which sound is audible, the
threshold of feeling being the lowest intensity causing a sensation of pain.
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