| Romy, are you sure the unborn fetus is exposed to sounds in the 200-400 Hz range? I think it's more of 30-200 Hz (conducted sounds of mother's heartbeat and footsteps). I think babies are also sensitive to these range of sound: they sometimes fall into sleep when hearing repetitive sounds in this range. There is a Japanese story about a baby who fell in sleep after hearing the sound of the O-daiko, or the big Japanese drum. |
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