What type of noise is typically used for pure-tone masking?

Narrow-band noise is the typical choice for pure-tone masking due to its specific frequency range characteristics that align closely with the frequencies being tested in a hearing assessment. This type of noise is designed to cover a narrow range around the frequency of the pure tone that needs to be masked. By utilizing narrow-band noise, audiologists can effectively obscure the test tone without affecting the assessment of hearing sensitivity for adjacent frequencies, which helps in making accurate determinations regarding a patient's hearing threshold.

Narrow-band noise provides the needed frequency specificity that allows the clinician to minimize the risk of masking for frequencies that are not being tested, thus isolating the response to the pure-tone signal more effectively than broader types of noise would. Shaped noise, while it can be used in certain contexts, is not typically favored in standard pure-tone masking protocols because it may not provide the required frequency isolation. White noise encompasses a wide spectrum of frequencies and may not efficiently mask pure tones, particularly if those tones fall outside its broad range. Pink noise, with its frequency distribution, also does not target the narrow frequency ranges necessary for effective pure-tone masking.