Whether it is a tweeter or a woofer, their frequency response curve is not flat. The tweeter and woofer will be attenuated at both ends, so that the upper attenuation part of the low-frequency sound may be the same as the lower-limit attenuation part of the high-frequency sound. Coincidence or even interleaving occurs, causing the frequency bands to overlap and fail to form a straight curve, so the sound will not be of good sound quality.

The function of the frequency divider is responsible for completing this combination of frequency response between each speaker to achieve better results. The frequency divider processes the music signal output by the power amplifier through the original filter to allow the specific frequency signals of each unit to pass. Simply put, the original signal is divided into several frequency bands, and the frequency divider selects the most suitable unit for playback The frequency band is allocated to it to realize the cooperative work of multiple speakers. Make their crossover frequency flatter, so that the sound becomes more perfect and beautiful when replayed.

Tweeters, woofers, midrange speakers, etc., as the name implies, these speakers can only accept the corresponding frequencies. If you add all frequencies directly to all speakers, some speakers will be damaged. For example, the woofer can withstand high pitches , But the tweeter cannot withstand the bass, and the sound is slightly louder and it will directly damage the treble.

The function of the crossover is to divide the input full-range sound into three frequencies: treble, midrange and bass, and then output to the corresponding speakers respectively, so that the sound is good and there is no need to worry about damaging the speakers.

The need of the frequency divider is determined by the design of the speaker itself. The double frequency divider is divided into two sections, and the three frequency divider is divided into three sections. This is what we often call "two-way" and "three-way". Divided according to the working principle of the frequency divider, it has a variety of implementation methods, which are divided into different types of designs, but we often see two major categories of power dividers and electronic dividers. The concept of being able to hear. Some special speaker speaker designs, such as high, medium, low, and bass three-way four-units, may require custom crossovers.

The frequency divider has a power range, such as 5～10W, 10～30W, 50～200W, etc. The power of the frequency divider must be greater than or equal to the speaker power, but it does not need to be too large, otherwise it may damage the frequency divider or excessive audio power consumption on the frequency divider, and the use of high-power frequency dividers on small speakers will increase funds.

For example: 

the frequency range of the bass speaker of the speaker is 45 Hz ~ 1200 Hz, 

the midrange speaker is 900 Hz ~ 5000 Hz,

the tweeter is 3500 Hz ~ 22000 Hz, 

then the crossover point of the frequency divider should be determined, and the bass should be between 1000 Hz ~ 1100 Hertz and treble should be between 4000 Hz and 4500 Hz.