"If you use iPod earbuds as a way of masking out environmental sound, it's probably too loud," Dr. Rauch said.

Based on the masking properties of the psychoacoustic model, we then derive the required sound pressure level of the watermark.

With studying different kinds of papers domestic and abroad about masking of tinnitus and measurement of tinnitus sound, we made sure that the masking device can cure tinnitus to certain extent.