Equalizers and digital sound processors (DSPs) are two types of devices that allow you to fine-tune the sound in your vehicle's audio system. Both can improve the sound quality of an audio system so that it better suits the ambient conditions of your car.

Car audio is inherently more complicated than home audio due to the irregular nature of vehicle interiors, so even great car sound systems can sound bad right out of the box. Your car’s interior is full of materials that absorb or reflect sound, which can result in some frequencies being muffled while others hit your eardrums like a truck.

Some head units include simple bass, treble, and midrange adjustments, but equalizers take things a step further. In a system with an amplifier, the equalizer sits between the head unit and the amplifier, and allows you to boost or cut specific sound frequencies.

There are different types of equalizers, each with its own advantages: