The middle ear amplifies sound pressure through three mechanical mechanisms

Evidence

The second function of the middle ear is to provide some protection for the hearing system from the effects of loud sounds, whether from external sources or the individual concerned. This occurs as a result of the action of two muscles in the middle ear: the tensor tympani and the stapedius muscle. These muscles contract automatically in response to sounds with levels greater than approximately 75 dB(SPL), and they have the effect of increasing the impedance of the middle ear by stiffening the ossicular chain. This reduces the efficiency with which vibrations are transmitted from the tympanic membrane to the inner ear and thus protects the inner ear to some extent from loud sounds. Approximately 12 to 14 dB of attenuation is provided by this protection mechanism, but this is for frequencies below 1 kHz only. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 541 (#expands, via linked claim)

Otoacoustic emissions—sounds generated by your own hearing system—are a condition everyone’s flesh is to some degree heir to, simply because the hearing apparatus, from ear to brain, works not only as a receptor but as an amplifier. — George Michelsen Foy, Zero Decibels, 329 (#expands, via linked claim)

Categorization

• XREF: connects to: The middle ear functions as an impedance transformer matching air to fluid; The middle ear evolved as an impedance transformer to bridge air-water sound energy loss — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 733; SOAE bouncing is not caused by middle-ear impedance changes (+11 more)

Related

• The middle ear both transmits sound and protects against loud noise (similarity 0.96)
• Middle-ear muscles automatically stiffen to block loud sounds (similarity 0.92)
• Otosclerosis stiffens ossicle movement and attenuates transmitted sound (similarity 0.90)
• Middle ear impedance match is optimal near 1 kHz (similarity 0.89)
• The middle ear evolved as an impedance transformer to bridge air-water sound energy loss (similarity 0.89)
• An acoustic reflex desensitizes the ear to protect cochlear hair cells (similarity 0.89)
• SOAE bouncing is not caused by middle-ear impedance changes (similarity 0.89)
• The middle ear functions as an impedance transformer matching air to fluid (similarity 0.88)
• The ossicles mechanically transform impedance to overcome fluid resistance (similarity 0.88)
• Outer and middle ear structures provide frequency-specific amplification of incoming sound (similarity 0.87)
• The ossicle-softer-ligament design protects ears by dumping intense-sound energy. (similarity 0.87)
• Outer and middle ear transfer function determines loudness across frequency. (similarity 0.87)
• Sound becomes mechanical movement via the eardrum and ossicle chain (similarity 0.85)
• Middle-ear impedance matching boosts pressure transfer roughly 30-fold (similarity 0.83)
• The eardrum converts air pressure changes into mechanical middle-ear vibrations (similarity 0.82)

Broader Connections

• Middle-ear muscles automatically stiffen to block loud sounds #expands (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 541
• The human ear itself generates sound as a byproduct of amplifying incoming signals #expands (0.85) — George Michelsen Foy, Zero Decibels, 329
• An acoustic reflex desensitizes the ear to protect cochlear hair cells #expands (0.85)
• Outer and middle ear transfer function determines loudness across frequency. #expands (0.80)
• Middle ear impedance match is optimal near 1 kHz #expands (0.80)