auditory masking
a reduction in the ability to detect, discriminate, or recognize one sound (the signal or target) due to the presence of another sound (the masker), measured as an increase in the detection threshold caused by the masker. The amount of masking is the increase in threshold measured in decibels (dB). For example, if the detection threshold with no masker is 10 dB SPL (decibels sound-pressure level) and the masker raises the threshold to 60 dB SPL, the amount of masking is 50 dB or, equivalently, the masker produces 50 dB of masking. The ability of one sound to mask another has been used extensively to assess the frequency selectivity of the auditory system. See also critical band; masking.