intensity just noticeable difference

The "just noticeable difference" (JND) in sound refers to the smallest change in intensity that a listener can detect. This concept is quantified by Weber's law, which states that the just noticeable difference is a constant ratio of the original stimulus. For sound, this means that the amount of intensity increase needed to be noticed is relative to the initial sound intensity.123

Sound intensity itself is the amount of energy flowing per unit area per unit time, measured objectively by equipment. The human ear has a vast dynamic range, meaning it can perceive a wide spectrum of sound intensities. The JND is crucial because the ear's response is nonlinear; it responds logarithmically to changes in intensity. This logarithmic response is why the decibel scale is used to measure sound intensity, as it better reflects human perception. A change of about one decibel is typically the smallest intensity difference the ear can detect.415