SHS 401 Principles of Audiology 2. Is masking necessary to obtain left ear bone conduction thresholds using supra-aural headphones? The LEFT ear is the TEST ear. Formulas: Is masking necessary: TE AC - TE BC > 10 dB Minimum masking level: NTE AC + 10 dB Maximum masking level: TE BC + 40 dB **enter "No" for minimum/maximum level if masking is not needed** Example Q20: 250 Hz Q21: 500 Hz Q22: 1000 Hz Q23: 2000 Hz Q24: 4000 Hz Q25: 8000 Hz Masking? Minimum level Maximum level Audiogram AC Unmasked (L) X BC Unmasked (L) > AC Masked (L) BC Masked (L) ] to Response (L) Y AC Unmasked (R) Q BC Unmasked (R)