Conversational speech moves the basilar membrane only about the diameter of an atom
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
Category: Factual Claims
- CANDY: Easy elevator fact: the ear drum/membrane moves the width of an atom and we still hear softer sounds.
- SHARE: To a physicist or audiologist who’d appreciate the mechanical surprise that hearing works at atomic-scale displacement.
Related
- Basilar membrane displacements during speech are only tens of nanometers, near atomic scale (similarity 0.95)
- Even very loud sounds move air by only about a micron. (similarity 0.81)
- A 40 dB 1000 Hz tone moves air atoms by only about one nanometer. (similarity 0.81)
- A just-noticeable frequency shift moves basilar excitation a constant 0.05 mm. (similarity 0.80)
- Just-noticeable frequency shifts map to constant basilar distances (similarity 0.80)
- Hearing spans a pressure range greater than a million to one (similarity 0.78)