Middle-ear impedance matching boosts pressure transfer roughly 30-fold

Evidence

The impedance-matching mechanism improves the pressure transfer by a factor of about 30; that is, by about 30 dB. The transfer function of the middle ear is a band-pass filter where mid-frequencies are emphasized, and the response rolls off at higher and lower frequencies, as characterized in Figure 7.5. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 734