Whether an equalizer is parametric or graphic, it can be mounted in the front of the car or trunk. EQs are mounted in the front for easy adjustment of different types of music or songs, and are meant to be used by the owner. These are usually octave or 1/2 octave graphic equalizers or four-band parametric equalizers. Typical locations are close to the radio or hidden in the glove box or console.
More complicated equalizers are usually adjusted once and stashed away in the trunk or other remote location. This is usually done by a professional, who adjusts the EQ according to the user’s taste. If you don’t know what you are doing you should not play with a complicated equalizer set up by a pro. Most often than not you will end up messing up the system. Typical mounting locations are in the trunk, back seats, or hidden inside panels.
The most important aspects of mounting locations for equalizers is noise sources and accessibility. Since equalizers work with low-level signals, they are prone to picking up radiated noise. RCA wires should be routed away from car’s computer and power wires (especially away from power wires going to amplifiers). They also need to be accessible for adjustments.
Equalizers are very easy to connect: Since active equalizers draw very little current, power and ground wires do not have to be as massive as amplifier’s wires. EQs also need a turn-on wire from the head unit.
RCA inputs and outputs should be carefully routed to avoid noise. The main concern is not the low current power wires from the equalizer, but power wires from the amplifiers.
As soon as an equalizer is installed, it should be adjusted to 0 or “flat” response (no boost, no attenuation). An equalizer is the LAST component in a system to get adjusted. See the tweaking section for more information in setting an equalizer.