Life and Family

Doing Your Job


Sound Systems

by Jim Park

Let's see, you spend 13 hours a day driving, another couple waiting around for something to happen, then countless hours in off-duty mode. And for most of that time, you're listening to the radio or playing a tape. So why settle for tin-box sound?

Many truck makers have come to the table with some decent systems, but you really can't beat the sound from a custom aftermarket installation. The cab of a truck hasn't always been terribly conducive to that option, but today we've got the room we need to install subwoofers and CD changers. And, wonder of wonders, the four-inch factory speaker hole right behind your ear is no longer the only place you can put a speaker.

So what do you buy? Your first decision may be to choose between CD and cassette. If you're still rather partial to tapes, consider buying a good cassette deck and toting along a portable CD player with a cassette adapter - but be sure it has the anti-skip function.

Current processor technology has virtually eliminated the annoying skip that occurred when a CD player experienced a jolt. It's smooth sailing all the way now, but why stop at loading a single CD? Many manufacturers now offer a multiple CD changer built right into the radio deck, or the head, as the manufacturers prefer to call them. There are also separate multi-CD changer units that can be mounted anywhere in the truck, then wired to the head and operated either manually from the radio or from a hand-held remote control.

Cassette or CD, an average-quality machine with enough power to drive a four-speaker system can be purchased for between $300 and $500, but you can also drop several thousand dollars if you're feeling so inclined.

If the power output of your off-the-shelf cassette deck isn't doing it for you, consider adding an amplifier, either integrated with a graphic equalizer or a stand-alone type. The brochures for some of these amplifiers advise using a 60-amp fuse for the power supply, so you know they're cranking out some serious wattage.

Big-league power amps don't come cheap, but a solid unit in the 50- to 100-watt-per-channel range shouldn't break the bank. Combine an amp with an equalizer to customize the sound and you're looking at slightly more, but a quality integrated amp and equalizer can be easily had for less than $300. If you plan to install a set of subwoofers or any more than four speakers, you should add an amp to your system, but beware of inflated power output ratings.

The lower-end products tend to rate their output using a term called 'peak power', which is basically the point just short of where the unit goes up in smoke. RMS, or continuous output, is a more meaningful unit of measure. A 50-watt RMS rating may well go to 200 watts peak, but that just means there's plenty of room at the top end for those big power surges that guys like Stevie Ray Vaughn can create when played at a prodigious volume.

How big an amplifier do you need? Choose the speakers first, then match the amp to their power requirements. For satellite speakers, 25 to 50 watts RMS is usually enough power for most people, but a subwoofer won't perform well when underpowered - which can destroy a speaker much faster that overpowering. Always try to match the RMS power of your amplifier to the RMS power demands of the speaker. This will result in the best performance and longevity for your system.

Speakers make the system, and nowadays truck cab designs offer lots of latitude as to where you put them. Forget about the four-inch 'full range' speakers commonly found in trucks and consider a component speaker system. These consist of a woofer and a separate tweeter, which can be mounted together or separately. Some consideration should be given to imaging, or how the sound seems to come together. It's a rather eccentric consideration, but if the speakers aren't positioned properly, even the expensive models will sound lousy.

A really nice addition to any mobile audio system is a subwoofer. They really round out the sound and fill the cab with deep, rumbling bass. Because low-frequency sounds aren't directional, placement of the subwoofer isn't that critical - try near the ceiling, under the bunk, or in the cabinets behind the seats. If there's no convenient location, a free-standing enclosure can be hung just about anywhere.

Here's a word of caution from a professional car audio installer, Adrian Brownfield of Vancouver. He advises that if you're getting into medium- to high-end equipment, you'd better let a professional installer do the dirty work.

"Warranty is the first consideration," he warns. "If you screw something up, it's yours. There's more than you'd think to assembling and integrating all these components, and there's plenty of room for mistakes."

At the very least, a professional installer will have a much better idea of how to get premium performance from the system in terms of speaker placement and component compatibility. And those few extra bucks will seem well worth it when cruising down the open road with your favorite artist crooning away over the roar of the engine.

Many mobile audio manufacturers have also combined the CD player with a DVD player, a gaming interface and monitor outputs so that you can now enjoy surround-sound movies or a good round of 'Duke Nuke 'em', while you wait for some bureaucrat to process your paperwork.

We've sure come a long way from the days of 8-track tapes.

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