According to the plateau method for determining true thresholds, the test-ear threshold remains stable over a range of at least how many dB increase in masking intensity?

According to the plateau method for determining true thresholds, the test-ear threshold remains stable over a range of at least how many dB increase in masking intensity?

• A. 10 dB
• B. 15 dB
• C. 20 dB
• D. 25 dB

Answer: (C)

In masking, the plateau method looks for a range where increasing the masker in the non-test ear stops affecting what you measure in the test ear. Once cross-hearing is eliminated, the test-ear threshold should stay the same even as you raise the masker. The point is that you want a wide enough plateau to be sure the threshold you’re recording truly reflects the test ear’s sensitivity, not leakage from the non-test ear. That plateau needs to be at least 20 dB in masker level. Having a 20 dB range where the test-ear threshold remains stable gives confidence you’ve achieved full masking and obtained the true threshold. If the plateau is narrower, the measurement may be more susceptible to changes in masker level or to residual effects like central masking, making the true threshold harder to pin down.

In masking, the plateau method looks for a range where increasing the masker in the non-test ear stops affecting what you measure in the test ear. Once cross-hearing is eliminated, the test-ear threshold should stay the same even as you raise the masker. The point is that you want a wide enough plateau to be sure the threshold you’re recording truly reflects the test ear’s sensitivity, not leakage from the non-test ear. That plateau needs to be at least 20 dB in masker level. Having a 20 dB range where the test-ear threshold remains stable gives confidence you’ve achieved full masking and obtained the true threshold. If the plateau is narrower, the measurement may be more susceptible to changes in masker level or to residual effects like central masking, making the true threshold harder to pin down.