Tuning up your car's audio system


Charlie Pastorfield

Charlie Pastorfield writes about car audio for Crutchfield. Raised in Connecticut and the U.S. Virgin Islands, he graduated from the University of Virginia, but was having way too much fun to leave Charlottesville. After a long, beautiful career touring the East Coast from Boston to Atlanta as a professional guitarist (Skip Castro Band, The Believers), he married Emilie, had two daughters (Morgan and Emma), and got his first full-time job at Crutchfield. Still an extremely active musician, he's now a member of The Gladstones, a 4-piece group that plays just about anything, and Alligator, an 8-piece band that plays late 60's Grateful Dead.

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Whether you're a car audio newcomer or a seasoned competitor, there's nothing quite like adding new audio equipment to your vehicle. However, it can be disappointing when your carefully designed system doesn't sound the way you expected it to. But don't lose your cool — spend some time tuning your system before you go back to the drawing board. Here are a few suggestions for maximizing your system's potential.

installing a car speaker

If your stereo sounds a bit off, check your speakers first.

Check speaker phase

The speakers in your system should all be firing in phase — simply put, all the cones should be moving out and in at the same time. If they're not, you lose bass response, which makes your system sound anemic and unfocused. It's important to check all your speakers, even if your system was professionally installed.

To determine if a pair of speakers in your vehicle are in phase, listen to some bass-heavy music with your stereo's balance control all the way to one side. Now return the balance control to the center — you should hear significantly more bass. If you don't, your speakers are out of phase. Switch the positive and negative leads on a single speaker, and try again. If you hear more bass, leave it! Use this method to check the front and rear speakers independently.

Turn on your subwoofer system. Reverse the speaker wires going to your sub and listen for a change in bass response. Again, if it gets louder, leave it alone. Another tip — always make sure that multiple subs are wired in phase with each other.

Setting the EQ

It may be tempting to crank up the bass on your receiver, especially if you've just installed a sub. But you really need to tune your system first.

Start with the receiver EQ set flat — all tone controls at "0" and no EQ curve engaged. With the subwoofer off, turn some familiar music up to a moderate listening level, then slowly increase the subwoofer output until you hit the "sweet spot" — the place where the bass really kicks in without overwhelming the rest of the music.

If the bass sounds like it's coming from behind you, lower the sub amp's crossover point to "de-localize" the bass. If your amp has a non-adjustable crossover, try moving the subwoofer. For example, if the subwoofer is firing toward the rear, turn it around so it fires forward or sideways. Remember to check your phase again when the sub is in its final position.

Creating a soundstage

Your system should create a "soundstage." What that means is that when you close your eyes, you should hear the instruments as though they're directly in front of you, arranged from far right to far left, with (if you're listening to a little rock'n'roll) the kick drum, bass guitar, and lead vocal right dead center. When your soundstage is set up correctly, it's like the band is playing a set on your dashboard.

bass blockers

Bass Blockers remove low frequencies, which helps front speakers perform better

Some vehicles make it tough to establish a strong front soundstage, but there are several workarounds that can help you get the sound you want:

  • If your car has small front speakers, install some Bass Blockers. They'll filter out the low frequencies so your speakers will play louder and clearer, bringing the soundstage back in front of you. If your receiver has built-in crossover capability, use its high-pass filter to remove low bass from smaller speakers for improved performance.
  • If you have a subwoofer (or larger speakers in the back), use your receiver's fader to move the music forward and then turn up the overall level to bring the bass back into play.
  • If your front speakers are mounted low in the doors, that can have a negative impact on soundstaging. Some receivers feature independent front/rear tone controls or signal processing that raises the front image, so make those adjustments of you can. Or, if possible, install a set of tweeters up front.

The right amount of bass

Great bass isn't just for rap, heavy metal, or reggae fanatics — if you're a fan of classical music or jazz, you might be surprised at the quiet authority a subwoofer brings to your music. Even at low listening levels, a sub can produce richness and impact you wouldn't otherwise hear.

Play some music that features active, powerful bass parts — all the bass notes should punch out at an even volume level. If you hear bass notes dropping out or booming, check your phase and experiment with different crossover points until it's smoothed out. Once your sub is tuned properly, you can use your receiver's equalization controls to make minor adjustments.

Instead of cranking the bass way up to increase your system's impact, raise the bass a little bit and lower the highs and mids. It's smart to keep equalization to a minimum — pumping up the bass control just robs your system of its effective power.

Anything missing?

After a few hours of listening, you'll be able to notice any weaknesses in your system.

  • System sound dull? Put a set of tweeters up front to strengthen your front image and add liveliness to your sound. Many receivers feature signal processing to enrich the sound, or extensive equalization which can do a lot to improve a dull-sounding system.
  • Vocals and instruments sound buried? If your receiver has a midrange control, boost it up a little bit; if it includes a parametric EQ, try adding a little bump in the 400-1000 Hz range. Replace your rear full-range speakers with high-quality midrange speakers to bring out warmth and detail without adding more sizzle. Installing Dynamat in your vehicle will reduce road noise, which masks crucial midrange details.
  • System too bright? If your front speakers have swiveling tweeters, aim them away from you. If you have installed component tweeters, check the crossovers for output level switching — a drop of 3 dB can make a huge difference in the way your tweeters match up to the rest of the system. Experiment with your receiver's EQ. If that doesn't nail it, consider a receiver with more equalization control or (for an amplified system) an outboard equalizer.
    equalizer screen

    A built-in equalizer is a big help in tuning your system

Think ahead

Once you've taken the time to adjust the system, you'll know whether or not you've made smart purchases. Always buy with an eye to the future — you might be saving 40 bucks on your receiver now, but what's the point if it's missing some crucial features you'll need when you expand your system?

If you plan on adding a sub to your system later, spend a little more now and get a multi-channel amp (instead of a 2-channel) so you can power your front speakers and subs with one amp. Oh, and don't install 10-gauge power wire if your ultimate goal is a throbbin' multi-amp system. If you're thinking big, thinking ahead can save you a lot of time and money when you're building the car stereo system of your dreams.

For more tips on how to build a great car stereo system in stages, check out this article about our Budget-Friendly Car Audio Buildup.

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