EQs are built solely and mainly for the purpose of fine tuning your sound as you see fit. Without equalizers signals and slight frequencies can be lost or even interact with each other. This problem is sometimes complicated more with the addition of more speakers to a system. This is drastically reduced next to gone with a good quality EQ, quality wires and proper wiring. If running a fairly powerful system it’s next to impossible to acquire the true sound quality potential that the speakers can produce.

EQs are differentiated to "Bands". It simply means the more options you will have to fine tune your sound. The generic radio may carry treble and bass. An EQ gives you more options beyond the basic sound settings. The more bands your EQ has the more tweaking can be done. An EQ generally breaks up the already delivered sound into (depending on your EQ system) as many possible sound frequencies as provided by the EQ unit. As the number of bands goes up on an equalizer the less interference you will get within your frequencies leading to being able to adjust maybe a simple hiss or annoying frequency you may here in any of your already arranged settings.