Basilar membrane displacements during speech are only tens of nanometers, near atomic scale

Evidence

The displacements of the basilar membrane are very small. Normal conversational speech produces sound pressures in the air of about 20 mPa or sound pressure levels around 60 dB. The associated displacement of the basilar membrane is in the amplitude range of tenths of nanometers, a size that corresponds to the diameter of atoms. However, we can still hear tones which have a sound pressure 1000 times smaller. Our hearing system must use very special arrangements to produce such an extraordinary sensitivity. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 226

Categorization

• CANDY: Conversational speech moves the basilar membrane by only atomic-scale distances yet we still hear 1000x fainter sounds — a striking bar conversation fact.
• QUESTION: What ‘very special arrangements’ achieve this sensitivity given such tiny basilar membrane motion at threshold?
• corroborated: 2 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 226