|MadSci Network: Physics|
Hi, The reason is that people always hear their own voice differently from what it really sounds like. When you speak, part of the sound (that which others hear as well) goes through the air outside the head and enters the ear in the normal way. However, the ear also picks up sounds from inside the head due to vibrations in the flesh and skull (tap your own head and compare the sound to tapping someone else's). Of course, the vocal cords and the air inside the throat will cause such vibrations and the sound you hear is the sum of outside sound through air and inside sound through the skull and flesh. Eustach's tube (a thin air duct between the throat and the inner ear that allows inside pressure to equalise with outside pressure) does not come in to play here, since it is closed when you speak normally. When you yawn you do sometimes hear sound coming in that way, but otherwise not. A curious side-note there is that when you are often confronted with your own voice in recordings (singers, radio hosts) you stop noticing the difference after a short while. Regards, Bruno
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