What is shifting frequency divider?

Move prescaler is a way to change the sound frequency equipment, works similar to the tone, it will increase the frequency of a sound signal, failure to produce 5Hz acoustic feedback, thus inhibiting the acoustic feedback. However, the use of the equipment have certain limitations, in the language you use sound reinforcement equipment allows to effect good, sound damage is very small, but in concert and instrumental music in use will have clear voice tone. This is because the language of the lower frequency range is between 130 ~ 350Hz 5Hz tone changes alone will not make it clear tones varying high feeling, but in vocal and instrumental music of lower frequency is about 20Hz 5Hz tone change obviously ear has been aware of it.