You have put together a system that is truly "bad" in the very best sense of the word. Yet even though your drivers and subs are properly placed, your crossover points are correctly set, and your head unit is pouring out clean CD sound, something is still missing.

Maybe the cymbal crashes lack that special sheen that makes it seem like you are close enough to feel the drummer's sweat fly from his head. Alternatively, your bass hits hard enough, but instead of the solar plexus punch you were looking for you ended up with a vehicle-quaking rumble. If your dream system's still aching for something to give it that final tweak, check out that often overlooked component, the equalizer.

Why equalize?

Like you, we have heard plenty of car stereo snobs dismiss graphic EQs as elaborate tone controls designed to mask a weak choice of components. While it is true that a graphic equalizer gives you ultra-precise tone control (call us crazy, but we think that is a good thing), a quality EQ, properly used, can fine-tune even a high-end system.

An equalizer makes the difference by catering to your listening preferences and allowing you to restore great sound that is disrupted by your noisiest, most hard to handle component ¡ª your car.

Most vehicles have a natural resonance frequency between 100 and 200 HZ, and most road noise occurs between 25 and 200 Hz. So even an otherwise perfectly balanced system gets a bump at these resonant frequencies, exaggerating them in a way that can muddy your sound and mask other frequencies. With a graphic EQ, it is easy for you to reach out and clean up your sound by cutting the offending bandwidths.

In addition, every listening environment, from a living room to a concert hall to your Chevy S10, has its own acoustic properties.

The glass in your car, a hard, highly reflective surface, can overemphasize highs and make for a particularly "live" (reverberation heavy) sound. On the other hand, the definition or "crispness" of your entire system can easily be dulled by absorbent surfaces like your car or truck's carpeted interior. Even differences in upholstery material, from smooth, reflective vinyl or leather, to more plush-textured seat covers can affect your system's sound.

You can use an equalizer to remedy each one of these ills, boosting the frequencies you are missing and attenuating the one's your vehicle exaggerates. In short, you will be able to restore the ideal, flat response of your music or customize it to suit your ears.

When you make these adjustments, use a light touch on those slider switches ¡ª a boost of 10 dB works your amplifier ten times harder, and this can introduce distortion. (Tip: Try attenuating frequencies first. For example, before you boost your bass, lower the midrange and high frequencies a little bit first.)

Of course, an EQ is also a great way to protect your equipment. For example, if your system's bottom-end is provided by a pair of 6-1/2" woofers, use an EQ to cut out all frequencies below 50 Hz. Your amp will work more efficiently and you will get higher, clean volume while protecting your drivers from tones they cannot handle.

Going beyond the basics

Besides restoring the desired response curve to your system, the equalizers available from also offer you plenty of other useful features. Each of our EQs offers a front-to-rear fader for dual-amp balancing, even with a head unit that has only one pair of pre-outs. The fader's also ideal for dialing in just the right amount of rear-fill.

In addition, you can take that concept one step further with one of our particularly "imaging-conscious" units.

You will also find a low-pass, "sub-out" set of pre-amp outputs on many of our EQs. engage high-pass crossovers on the front and rear channels whenever the subwoofer output is in use. That is like having a free electronic crossover packaged with your equalizer ¡ª a pretty sweet deal.

The 11 band 6042A also gives you two bands with adjustable center frequencies (30-800 Hz and 800-16kHz). These parametric (variable) bands really let you zero in within a given frequency range. Therefore, it is a snap to dial up your favorite lead guitar sound, from smooth, violin-like sustain to a percussive snap and twang.

When using any equalizer, the more you know about which frequencies are produced by which instruments, the more effective your adjustments will be. Within the range of a given instrument, tonal shading can get downright subtle.

For example, the meaty bottom-end of a bass guitar is found around 60 to 80 HZ, the attack (the percussive sound of the string being plucked) ranges from 700 to 1,000 Hz while the string noise itself is up around 2,500 Hz! In addition, that is why an EQ can be so handy!

Some EQs, let you program your own EQ curves and store them for repeated use. Therefore, you can create one curve for rock, another for rap, a third for jazz. After all, each of these musical forms naturally emphasize different tones, from the bottom heavy thump of Coolio to the scooped-mids of Metallica to the pastel horn tone of Miles Davis.

The best way to find out what an equalizer can do for your system is to try one out for yourself. A little "hands-on" experience and some trial and error tweaking will help you learn more about shaping up the sound in your car and really bring out the best from your system.