With all the power an variables that you can get from your system, being able to fine tune is gold. Sometimes, the difference between a good and great system, is the equalizer. Many receivers come built-in with an equalizer, but most of these give you very limited controls. Just by adding an external equalizer, you will be able to make fine adjustments. Remember to make very light adjustments though, as the signal will be amplified many times as it goes through the amplifier.
Even with a good setup, the result of sound bouncing off various surfaces in your vehicle can produce an undesirable result. This is when equalizers proof its worth giving you the ability to tweak the signals to your hearts content. EQ’s can also help protect quipment by limiting frequencies that your speaker drivers can’t handle.
Here are a couple of things to lookout for when picking an equalizer
Inputs and outputs
Be sure the number of inputs and outputs suit your needs
Fader
Some EQ’s provide fader adjustments even though your receiver has only one pair of outputs. Fader controls are really useful in fine tuning the rear fill
Subwoofer Outputs
These work like crossovers, allowing only certain frequencies to be sent to the subwoofer.
Number of Band adjustments
The more bands means finer tuning