What is the purpose of having different processing sections

What is the purpose of having different processing sections for different frequency bands

Solution

Generally, speaker drivers are incapable of convering whole spectrum of frequencies with acceptable relative amplitude and minimal distortion. So combination of processing sections have to be used in which each section processes a different frequency band. Crossover split devices are used to split the entire band into small bands and route it to various processing sections as per the frequency band they are selected for.

After processing of signal bands, they are mixed again. Thus we get desired gain or amplitude for respective band of frequencies.