Demonstration 13. Pitch Salience and Tone Duration (0:50)


In this demonstration three tones of increasing duration are presented. Notice the change from a click to a tone

Three tones

How long must a tone be heard in order to have an identifiable pitch? Early experiments by Savart (1830) indicated that a sense of pitch develops after only two cycles. Very brief tones are described as "clicks," but as the tones lengthen, the clicks take on a sense of pitch which increases upon further lengthening.

It has been suggested that the dependence of pitch salience on duration follows; sort of "acoustic uncertainty principle" ,

Δf Δt = K,

where Δf is the uncertainty in frequency and Δt is the duration of a tone burst. K which can be as short as 0.1 (Majernik and Kaluzny, 1979), appears to depend upon intensity and amplitude envelope (Ronken, 1971). The actual pitch appears to have little or no dependence upon duration (Doughty and Garner, 1948; Rossing and Houtsma 1986). In this demonstration, we present tones of 300, 1000, and 3000 Hz in bursts of 1, 2 4, 8, 16, 32, 64, and 128 periods. How many periods are necessary to establish a sens of pitch?