[SoundStage!]Fringe with Greg Smith
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June 1998

Drivers for Drivers

Just about everyone I know has at least one car they drive around. With very few exceptions, the car stereos found in those vehicles sound awful. Sometimes this is the owner's fault. Quite frequently I'll find bizarre equalization settings that, while being far from accurate, make the person listening happy. But in most cases no amount of fiddling with the available controls will provide anything better than mediocre sound. The parts involved just aren't of high enough quality. The question, then, is what to do about it. If you're looking to improve how a car stereo sounds, the easy way is to throw the whole thing away and hire some fancy installer to give you a megabuck rig that you can show off to all your friends. If that sounds like a good idea to you, go grab any of the monthly magazines devoted to car stereo and have fun. But if you're looking for a more reasonable approach that doesn't involve spending so much cash, keep reading. This month I thought I'd take the case-study approach and talk about five different cars I've installed upgraded sound systems in.

1983 Toyota Celica GT-S

I was 19 and I felt pretty cool cruising around town in this little "I wanna be a sports car when I grow up" set of wheels. When I got the car, much used by the previous owner, the original factory sound system was still intact. It was also awful. The speakers, well, sucked, and I had serious doubts about the long-term survival of the head unit. The biggest improvement per dollar in this sort of situation is always to replace the speakers. In this case, the front dash housed two 3 1/2" units, while the rear deck had two 4" cut-outs filled with a woefully inadequate excuse for a woofer. As I wasn't yet a mail-order guru, I went to the local electronics chain store and bought the only thing they carried that would fit in those spaces: four Pioneer drivers, each with a little coaxial tweeter in the center of the cone. Installing them myself was a long exercise in locating hidden screws, but with some help it only took a few hours. The system still didn't sound great afterwards, and there was almost no bass, but it was far better.

I acquired a replacement head unit through a complicated trade that I don't recall the mechanics of anymore. My cousin led me to a place with deep discounts (and questionable procurement) selling Pyramid equipment, so I picked up an EQ/amplifier combination dirt cheap. In a car, having some equalization to play with is far more helpful than in a home because you don't have the ability to move speakers around and such to compensate for problems. I spent a very hot day learning how to install these two beasts by hacking up all kinds of wiring inside the car. Afterwards, I still had no bass, but that old Pyramid amp had a subwoofer output. Somebody had given me two 8" woofers of limited capability a few months before that. I didn't know yet that speakers didn't actually do much of anything unless put in a proper enclosure, so I just sat them on the floor behind the front seats and ran some speaker cable to them. I then had a little bass, but still not much.

Disgusted by the whole experience, I got rid of the car. OK, so there were reasons other than the stereo to unload it, but the bad sound made me feel even better about selling it. What did I learn from this experience? First, if you're going to install everything yourself, you should at least buy from somewhere that offers a few choices of component brands. I would have saved money, gotten better drivers, and received far better advice dealing with a place like Crutchfield than I got at a store more worried about selling refrigerators than car stereo. Second, installing head units and amplifiers without all the right tools and adapters leaves behind a messy wiring job you wouldn't want to inflict upon a newer car.

1993 Chrysler Concorde

When I went to buy my first nice car, there were a lot of things I wanted. An excellent factory sound system was high on the list because I was nervous about financing such a large purchase. There was no way I was going to tear this car up and risk damage installing new equipment. Luckily, the premium Chrysler/Infinity system was quite adequate all by itself. Underneath the windshield were two 3 1/2" coaxial drivers and a slightly smaller center-channel to help with off-axis imaging (and when you're sitting in a car, you're just about always off-axis). The fronts doors contained 5" woofers that played below 250Hz. The rear deck housed two 6"x9" woofers with separate tweeters. In the trunk was a big amplifier that drove everything. The factory system was a really complicated electronic crossover and amplification setup that actually biamped the coaxial drivers. In addition, there was a bass management system that controlled what all the woofers were fed based on how the front/rear fader was positioned. So even if you were listening to just the front speakers, low bass would still come out of the bigger drivers in the rear. This tightly integrated system remains the best factory sound system I've ever heard, and as car stereo goes I've only heard it outperformed by some very expensive custom installations. The attention to detail was very thorough. For example, one day I took my Radio Shack SPL meter and graphed the system response while playing with the five-band parametric EQ. I discovered that the center frequencies for the five bands were very close to the middle of the worst problem areas in the overall response.

That measuring exercise pointed out something to be wary of when listening to factory systems. The bottom of the five EQ controls was centered on 60Hz. With that slider in the middle position I noticed a bit of a boom in the bass, which was caused by a substantial boost of 6dB in the "flat" position. To get accurate response, you have to drop it all the way to the lowest point. Some later reading on the system confirmed that this was an intentional part of the design. It's not necessarily safe to assume that just because a car system has all its controls at the center settings that you're getting the smoothest response.

The biggest problem with the factory system was the woofers on the door panel. When I played material with certain bass notes, the plastic door would resonate very badly and distort the music. I couldn't really pinpoint the problem with regular test tones, but I discovered one day while listening to the radio that the resonant frequency of the whole assembly happened to be very excited by playing Soft Cell's "Tainted Love." This left me in the embarrassing position of needing to play that song in order to test out treatments. Ultimately, I ended up using a 5 1/4" slim-line XTC baffle to erase the vibration (these are available from Crutchfield). These small pieces of molded foam fit between the door and the driver, damping their interaction while providing something a little closer to an enclosure than the big pocket of air behind the door. This $6 upgrade transformed the sound of the front woofers; Chrysler should install a set on every car they make. Bass was much tighter, and the driver would play louder without rattling the door. There are a huge variety of products that can be applied to a door to dampen it or help keep out external noise. It's worth trying out your local auto parts store for this sort of thing before spending big bucks on audio-specific designs at premium prices.

After this, the low frequencies were good, but only really had any real power down to around 40Hz. I built a subwoofer that fit in the trunk and went looking for an amplifier to drive it. As soon as I tried to tap into the Infinity system, I realized I had a couple of show-stoppers on my hands. The bass management system meant that I couldn't find any point to get a regular line-level signal that accurately represented the bass I wanted to feed to the sub. The only hope was to tap the speaker level signal going to the 6"x9" drivers in the rear deck. The wires leading from the amp to there were just barely long enough to reach, which meant I was treading on dangerous ground trying to splice into the cable. Besides, I was in no mood to start cutting anything in that car, as it was several years away from being paid for at that point. This meant I needed to fabricate some sort of extension cable that fit between the existing wiring and speaker. Apparently, the connectors used aren't widely available. I found adapters for the speaker side from Crutchfield, but not the matching plug for that to fit into. Nobody I could talk to at Chrysler or my local car dealer were the least bit interested in helping me find these proprietary plugs, and the car was a new enough model that none of the local junkyards had been graced with one yet. So the subwoofer never did get connected. This is a constant problem with the really fancy premium systems in cars nowadays. I've watched many people try to upgrade some component in the popular Bose car systems, only to find that there were no suitable replacements available from anyone else. You're often locked into the manufacturer's parts if you even need service or want to try something new.

I had a bit better luck with adding a CD player (I couldn't find the car anywhere with all the other options I wanted and CD too). Chrysler sold a woefully overpriced six-disc changer for this car. Not only wasn't that nearly enough discs, I was not enthused about the quality or cost of that upgrade. When I looked into after-market changer upgrades, I was back to the same problem as before: compatibility. Nobody could say for sure that they could make a CD player connect directly to this system without replacing the whole head unit, and that just wasn't an option. I'd have lost all the custom features that made this system sound so good. The only solution that worked was to get a changer that worked by FM modulation. These models inject their signal into your car's antenna at a specific frequency, so you select the CD player by tuning to its station. This limits the quality of your CDs to what FM can transmit, which mainly means you lose a bit of the top-end. I ended up with a Kenwood changer that sounded much better than any other source I had available for the car, but I was bothered by a bit of hiss and some electrical noise with this setup. In soft passages, I could hear the car accelerating in the background of the music. Not a perfect solution, but an acceptable one for my purposes at the time.

1981 Oldsmobile Delta 88

My father knew the Oldsmobile he was using wasn't going to last much longer, but the crappy sound was driving him crazy. Spending real money upgrading it would have been silly given the expected remaining life span of the car. The existing head unit was still mechanically intact, playing tapes just fine, but was obviously of low power. In a car of this size, where there are usually only passengers in the front seats, the quality of the rear speakers isn't a huge issue. The front speakers are what you hear most of the time. What was really needed to give the audio in this car a boost were a set of speakers for the front that would sound good even with very little power driving them.

When helping a friend upgrade his Ford Taurus, I got to hear some of the drivers from Blaupunkt. These inexpensive speakers had excellent specs, with considerably higher sensitivity than most of the competition. Many cars on the road utilize standard 3 1/2" units in the front of the vehicle. The Blaupunkt PCx352 is under $40 a pair, and they sound amazingly good for the money, even when driven with little power. I called Crutchfield, had them verify a good fit in my father's Oldsmobile, and ordered a set.

The main difficulty with installation was getting the 15-year-old screws backed out. The front speakers in this car are located near the intersection of the dashboard and the windshield, which means there's only a few inches of clearance above them to cram a screwdriver into. The only thing I could find that would generate enough torque while fitting in this tiny space was a Swiss army knife with a Phillips-head tool. After removing the decayed Olds speakers, the Blaupunkts slipped right in their place with little fuss. Crutchfield threw in the right adapters for the factory wiring for free with the order. The upgraded speakers helped restore my father's sanity while driving, and the price was right. Spending even a little bit on the speakers that matter most can provide an immense improvement in how enjoyable a car stereo is to listen to.

1997 Geo Prism

When I went shopping for a small, inexpensive car that would cut down my commuting costs, one of the things I expected was that I'd end up with a crappy car stereo in the process. While the regular system in that car is your typical ho-hum factory installation, there was a premium upgrade available that was well worth the extra money. There's a large space available for a head unit in this car, and Delco utilizes that with a double-height, combination CD/cassette source. There's no complicated EQ, but there are a set of music settings that apply often laughable "corrections," like a "pop" setting with boosted bottom- and top-ends. Amusingly enough, the "classical" setting is a flat response. I find the "rock" setting, which boosts the bass a bit, helps compensate some for the drooping low-frequency response of the fairly small drivers without becoming too boomy.

Most surprisingly, the factory system includes component speakers for the front. The tweeters are mounted above the dashboard, firing around head level, while a pair of approximately 5" woofers are mounted in the door. I haven't traced out where the crossover between the two is located; if the parts are attached to the drivers themselves, this could make upgrading the components individually difficult. The rear deck features two 6" drivers.

While this system generally sounds good, I only lasted about a month before I was compelled to install a simple upgrade. The head unit works very well, and the front speakers are of surprisingly good quality. However, there was something wrong with the midrange in the car, and I didn't quite peg down what it was until I put on a Don Henley CD one day. There was a horrendous peak right in the middle of his vocal range, which approached a painful emphasis when the volume was turned up. Using the fader to switch between front and rear speakers, all of the nasty stuff was coming from the rear. Those speakers had to go. When I looked closely through the grills, the source of my trouble was obvious. In a cost-cutting measure, the less important rear speakers were skimped on. The cheap 6" woofer had a little whizzer cone in the middle to try and extend the drivers' high-frequency response. I suspect that the emphasis I heard was right around the resonant frequency of that tiny cone. The obvious upgrade was a true coaxial driver for the rear speakers. Most of the really good drivers of that size you can get for a car really need more power than the head unit I have provides.

The best compromise between quality and sensitivity I've found for this kind of application is the 6 1/2" JBL GTC-6210, which list at $130/pair but are seemingly always on sale at Crutchfield for around $70. They weren't able to provide me with adapters for the factory wiring speaker connectors on this particular car, which meant another round of splicing that made this substitution irreversible. They did give me something much more important, a plate to adjust for the non-standard cut-out in the rear deck. I went through the usual trials of installation, including the discovery that the woofer/plate combination would only fit in one orientation (something you don't discover until after you try to put the car back together). But after a couple of hours of sweating outside in the summer heat, I had everything back together again-and the vocals sounded correct once more. There's still a hint of an emphasis in the original problem range, which suggests that there was some acoustic reinforcement involved in addition to the driver inadequacy. Overall, though, the quality is superb for the money invested. I wouldn't mind a bit more power for cleaner reproduction at higher volumes, and a subwoofer for full-range response would be nice, but other than those minor concerns I'm very satisfied.

1984 Toyota Camry Hatchback

After some of the cars I'd been dealing with, this older Camry felt like a wide-open system I could easily modify. My sister wanted something a bit more refined than the dull factory system provided. A new head unit had already been added by necessity, as the original started eating tapes, so speakers were the obvious upgrade. I spent quite a while shopping around for something that fit, and eventually came to the realization that nothing was going into that space without major work except some Pioneer units very similar to the ones that went into my old Celica. Having come full-circle, this time I bought them from Crutchfield, saved quite a bit of money over retail, and got complete installation instructions that detailed exactly how put them in. They didn't have adapters available for using the factory wiring directly, so I had to splice in some of the quick-disconnect cable supplied with the speakers into the system. The fairly cheap drivers are a huge step up from the original installation, even if they aren't really of the highest fidelity on the grander scale.

Not quite ready for the IASCA yet

Years of sporadically installing car stereo equipment still hasn't left me totally comfortable with the experience. Newer cars in particular are tough to work with because it's so easy to either introduce an electrical problem or disrupt the careful fit and finish during reassembly. And some of the premium factory systems, particularly the ones with big name brands involved, are nearly impossible to upgrade through normal means. The flip side to all this complication is that the preinstalled systems are far better today than they used to be. If you approach your audio concerns carefully, you can often find very simple and cost-effective upgrades that make your music even more enjoyable to listen to while driving.

.....GS (gsmith@westnet.com)

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