The just noticeable difference (jnd) in any parameter, such as PITCH, LOUDNESS and duration. Also called the difference limen. As can be seen in the graphs below, each of these depends on the frequency range and intensity level of the tone with respect to which the difference can be detected.
In general, the ear is most sensitive to slight changes in the range of 1 to 4 kHz and this sensitivity increases with intensity. For the dependence on duration see CLICK. The results quoted below are obtained under laboratory conditions with PURE TONEs, whereas in practice with complex tones, the individual's sensitivity will depend on training, environmental factors and hearing loss.
See also: CRITICAL BANDWIDTH, MINIMUM AUDIBLE ANGLE. Compare: PERFECT PITCH.
The variation of Df / f with frequency f, where Df is the minimum perceptible frequency change. Numbers on the curve indicate levels above the threshold of hearing (from Olson, Music, Physics and Engineering, Dover, 1967, p. 248, after Shower and Biddulph, used by permission). The minimum perceptible change in intensity level of pure tones as a function of frequency. Numbers on the curves indicate level above threshold (from Olson, Music, Physics and Engineering, Dover, 1967, p. 254, used by permission).