Any noise in dreams is a way of catching our attention, of focusing our minds. ?White noise? is a noise containing all of the audible frequencies of vibration; it is a good ?masking? agent when meditating or preparing for sleep used as a spiritual discipline. Any external noise can often be incorporated into dreams as part of the dream content. A bell ringing, for instance, might become a school bell. When we hear a strange noise in our dreams, we can expect the unexpected and the unknown in waking life.