ABSTRACT
Most sound sources involve a vibrating object of some kind. Regular vibration produces sound waves that repeat over time, such as the pure and complex tones described in Chapters 2 and 3. Within a certain range of repetition rates, we perceive the periodic sound wave as being associated with a pitch. It is important for us to be able to identify the repetition rate or fundamental frequency of sounds. The variation in the fundamental frequency of vowel sounds in speech can be used to convey prosodic information. Many musical instruments produce complex tones, and the fundamental frequencies of these tones can be varied to produce different melodies and chords. Less obviously, differences in fundamental frequency are very important in allowing us to separate out different sounds that occur at the same time and group together those frequency components that originate from the same sound source. These aspects are discussed in Chapter 10.
