How do I adjust my equalizer?

How do I adjust my equalizer and what do I need to listen for? 

What are the correct settings for my EQ? 

Is there a best way to set the controls of my equalizer?

Equalizers are used to help compensate for acoustical inaccuracies common in the automobile environment. The boost/cut controls on the equalizer increase or reduce emphasis in a specific octave of music. When used properly, an EQ can help overcome dips and peaks in the response curve.

What to Listen For

The sound of the audio system should be natural without excessive "hot spots" in the audio spectrum. A breakdown of the audio frequencies are listed below:

Sub-Bass: Low frequencies produced by bass guitar, kick drums & drum machines should be easily recognizable and not be over-exaggerated. A desirable bass level should be present at the same relative amplitude as the rest of the frequency spectrum.

Mid-Bass: Middle bass frequencies produced by bass guitar, piano and synthesizers should be reproduced with good detail. Listen to the intensity of drums and bass guitars because many vehicles have resonating problems (vibrations & rattles) that cause peaks in the response.

Mid-Range: The middle frequencies produced by the human voice, guitar, percussion and brass instruments should sound realistic without any harshness or distortion.

High-Frequencies: The high frequencies produced by cymbals, snare drum and higher notes on percussion instruments should sound accurate without excessive brightness. No blurring or hissing of the human voice should be heard.

To Boost or Cut? 

Although it's tempting to crank up each equalizer's setting to the maximum boost level, this rarely achieves the desired result. What you're actually doing is just increasing the amplitude of the system. By turning up the amplifier's gain control, you can also achieve the same result and thus increase the signal-to-noise or "hiss" in your system (this is not necessarily a good thing).

How to Equalize Properly 

Although it sounds strange, we recommend setting the equalizer boost/cut controls to the center (flat) position and using the EQ as a "cut-only" device. Use the equalizer to minimize the differences between neighboring frequencies. Use the equalizer to keep acoustic deviations under 3dB. If you find that you are using 9dB or more to "fix" a problem area, suspect something incorrect in the system design such as an incorrect crossover setting, improper speaker phase, or even a blown speaker.