Ok, for background: http://en.wikipedia.org/wiki/Acoustic_reflex
We all know that prolonged exposure to loud sounds can tire this reflex, resulting in more hearing loss, and that the non-instant reaction time of the reflex is why it's crucial to wear hearing protection if you're a carpenter or metal worker (hammering), etc etc.
But what i'm amazed about is this factoid:
20dB ?? That seems like an awful lot. According to the article it can be induced by humming, and they suggest it as an additional protection against hearing loss: hum just before and while hammering, etc.The stapedius reflex is also invoked when a person vocalizes. In humans, the vocalization-induced stapedius reflex reduces sound pressure levels reaching the inner ear hair cells by approximately 20 decibels.
If i listen to some music and hum, it certainly doesn't seem as if anything is attenuated 20dB... in fact, it sounds totally unaltered... which suggests to me that either the perceptual processing of the sound compensates for the physical attenuation, or that my stapedius ain't stapedin'.
Any thoughts on this? The wiki article isn't well-sourced, and i haven't dug around looking for other articles yet, but thought i'd throw it up here.
-c