Which type of masking noise is typically used for air conduction (AC) masking?

Narrow-band noise is typically used for air conduction (AC) masking due to its specific frequency characteristics. When testing hearing, especially in situations where there's a possibility of cross-hearing, narrow-band noise serves as an effective masking agent. This type of noise is designed to cover a specific range of frequencies around the test tone, thereby preventing the non-tested ear from responding to the sound.

In audiometry, narrow-band noise is preferred because it minimizes the risk of excessive loudness (which could occur with broadband noise), while still providing adequate masking for the frequencies being tested. This targeted approach ensures that the results are accurate and reflect the true hearing capabilities of the individual being tested.

While white noise, speech noise, and pink noise are also types of masking noises, they either cover a wider range of frequencies or do not provide the focused masking that narrow-band noise does in the context of air conduction testing. White noise encompasses all frequencies and may be too loud for certain frequencies, whereas speech noise contains vocal frequency energy that could interfere with hearing tests. Pink noise, similar to white noise but with a different frequency distribution, also lacks the specificity needed for effective AC masking. Thus, narrow-band noise is the most effective choice for this purpose.