The perceptual attributes of a sound can be different from the physical properties that characterize it. For example, the physical property of [[fundamental frequency]] (measured in Hertz) corresponds to our perceptual attribute of [[pitch]] (measured in musical notes or semitones). Another example is that the physical property of [[intensity]] (measured in decibels) corresponds to our perceptual attribute of [[loudness]] which can measured subjectively as soft, medium, or loud. Additionally, the physical property of [[duration]] (measured in seconds) corresponds to our perceptual attribute of temporal extent or [[timing]]. The relations between perceptual and physical attributes of sound can be summarized in the following table. | **Physical Quantity** | **Perceptual Quality** | | ------------------------- | ---------------------- | | [[intensity]] | [[loudness]] | | [[fundamental frequency]] | [[pitch]] | | [[power spectrum]] | [[timbre]] | | [[duration]] | [[timing]] |