Monday, November 12, 2007

Setting up a CAR audio system

DIY or go with a pro?

Once you've picked out your electronics, you have to decide whether you are going to install them yourself, or let a professional installer do it. Maybe you're handy with small repairs, or maybe the thought of installing speakers yourself seems daunting but you don't know what qualities to look for in a professional installer. Here's some help.

The Pros of Pros

If you have any doubts, save yourself lots of grief and use a pro. Cars are more complicated today than ever before. Even basic models are packed with computer controls. Today's state of the art upgrades-audio systems, navigation systems, even DVD systems-and their operating systems are interlaced in delicate and intricate ways.

Meddling with these critical systems can shorten the life of your vehicle and even endanger your life. Electrical problems, unseen shorts, wire deterioration, structural changes and loose connections could become safety issues.

Before you decide to let anyone work on your car, check his or her credentials. The Mobile Electronics Certification Program (MECP) administers a written test on the science and installation of car sound. Make sure your installer is MECP certified. Are they an ASE (Automotive Service Excellence) certified mechanic? Ask.

Check references as well. Ask to see examples of previous installs and speak with previous customers. Deciding on a professional installer is a lot like finding a reliable contractor or plumber.

Power tools don't frighten you

If you're good with minor repairs, like changing your spark plugs, you probably won't be intimidated by installing a sound system and you might consider doing it yourself.

There are lots of good reasons to self-install. If you've got the time, and enjoy the challenge, doing the install yourself might be pretty exciting. Customizing your own car is a great way to express your creativity. Poking around in the interior of your car makes you, well, "intimate" with your automobile.

Manufacturers and retailers are usually very helpful when it comes to DIY installs. Rely on them for parts, wiring harnesses, tips, templates and general good advice. Like this:

Avoid some of the pitfalls of doing-it-yourself simply by keeping some common-sense guidelines in mind:

  • Read the instructions completely before you begin.
  • Don't take your car apart until you're certain you have all the tools you'll need to put it back together again.
  • Avoid unnecessary discharge: disconnect the negative battery cable before you begin.
  • Protect your upholstery with a drop cloth, and don't carry tools in your back pockets!
  • Give yourself plenty of time, don't rush-don't force anything.
  • When in doubt, stop and ask directions. Reread the instructions.

Defeating distortion and stifling hum in your system.

Hiss. Hum. Noise. Every system is going to have some noise. Unless you're going to enter a sound competition, you may not even have to worry about it. Usually, you won't hear that small hiss when you're driving. But if you're concerned, you can test your system. Make sure your amplifier is isolated from your car's chassis. Then, try this:

Check your RCA patch cords. Disconnect the cords from you amp and reinsert just one strand into the right and left input jacks of your amp. Now start your engine and turn on your system. If you get noise, try re-routing your cords, separating them from other connectors (like your power cable) by at least 18". Also, try a better quality of patch cord, consider trading in coaxial cable for "twisted pair" cables.
Check your antenna. Unplug it and see if the noise goes away. If it does, you need an antenna noise filter.

Check your head unit. If you stop hearing the noise when you jiggle or pull out your head unit while it's playing a tape, the noise may be radiating from an ungrounded component into your tape or CD system. Try shielding the back of your head unit with metal foil (available at retailers) or filtering the unit's power leads.
Check the electrical system. Is your battery filled? Have a mechanic check your alternator and give your car a tune up. A tune up will stop the noise at its source: the spark plugs, wires, distributor cap, and coil. Install resistor-type spark plugs with shielded carbon-core wires. Worse case, have a mechanic check the grounding of your ignition, charging, and injection systems. All of these things can radiate noise into your system.

Defeating Distortion

"Distortion" can destroy your speakers. Distortion is the audible expression of a speaker's limitations or an amplifier running out of clean power. Distortion happens when speakers are forced to play frequencies that they were not meant to play, which happens when speakers lack the proper crossovers (frequency blockers). If you don't have the crossovers, and you jam low frequencies through your little tweeters, you will hear distortion.

Since beauty, as it were, is in the ear of the beholder, there's lots of argument over what distortion actually sounds like. But it's safe to say that when the stuff you're listening to gets "muddy," when it starts to lose the definition of individual elements, when it all starts to blend together into a loud jumble… That, my friend, is distortion.

If you start hearing distortion, turn it down!

Distortion is bad. Power, on the other hand, is good.

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