You know those luxury car commercials where it seems the passengers are enjoying life like they were perpetually in a day spa? I always thought those commercials were completely unbelievable, but now I know that those people were actually listening to Polk Signature Reference (SR) component speakers. It all makes perfect sense when you hear them. Wood paneling and leather seats might be nice, but a vivid, life-size musical experience is the real key to luxury driving. I know, because I have neither wood paneling nor leather seats, but everyone wants a ride in my 11 year-old Honda Civic, which happens to be equipped with a set of Polk SR5250 speakers.

The Polk SR5250 component speaker system

The installation

I won't lie to you; retro-fitting these speakers into my car was no picnic, partly because the crossovers are massive — in a good way — and partly because Honda isn't kidding when they call my car a "compact." There was virtually no room for any extra wiring. Nonetheless, many parts of my installation were like your standard, run-of-the-mill component speaker installation . I swapped out the full-range speakers I had in the door with the Polk woofers, and drilled other holes to accommodate the tweeters. (Polk is kind enough to provide four different mounting options for the tweeters: flush- and angle-mounts for a component set-up, plus regular and angled attachments for a coaxial set-up, which they cleverly call a "compaxial." They also provide mounting plates in case you have 5"x7" speaker holes, for even more mounting options.)

I had to get a little creative when mounting the crossovers — they ended up in the "pocket" in my doors, and required drilling a few extra holes to accommodate the wiring. At the time, as ideal mounting locations were becoming scarce, and my patience was wearing thin, I kept thinking, "is this worth it?" Well, I only hope that my writing skills are up to the challenge of convincing you that, yes, the thousands of hours of exquisite sound you end up with are well worth the incomparably few hours of installation time.

The crossovers were too large to conceal in my Civic, so I chose to mount them in my door's storage pocket

But before I get ahead of myself, I want to point out that another reason my installation took a while is because I also added an amp to my system. These speakers all but require external amplification (Polk recommends powering the system with no less than 50 watts — the system's continuous power handling is rated at 125 watts). I used the Polk/MOMO C400.4 4-channel amp, bridged to two channels for a grand total of 150 watts per channel. There would be no point in running such beautiful-sounding speakers from an in-dash stereo, which can usually only provide enough power for average speakers. When you're paying $750 for speakers, it's likely you can spring for an amp, too. Not that $750 is a lot to pay for these speakers. The tweeters alone are of the same design as found in home speakers costing upwards of $35,000. And don't even get me started on the crossovers.

The crossovers

Ok, I'll start with the crossovers. Did I mention that they are huge? Here's why: they employ all the best materials, like Mylar capacitors, gold-plated screw terminals, and a cast aluminum body, plus a few extra-special features. For instance, the resistors and capacitors are made to be tolerant of only 1% difference between their nominal value (their value on paper) and their actual value (their performance in reality). This means that you can count on the blending between the highs and lows to be virtually seamless, and the stereo imaging near flawless. The inductors also claim special-feature status. An inductor with an iron core will increase or decrease in value as the current ebbs and flows, muddying the frequency response. Polk's SR series speakers feature inductors with non-magnetic "air cores," which cut out the core's influence on the inductor's value, thus decreasing distortion and improving dynamic range.

Close-up of a crossover with the cover off

Finally, the crossovers employ what are called Zobel networks. To cut a long story short, these networks flatten the impedance curves that speakers naturally create, so you get the most output for your input, and the most accurate sound possible.

The woofers

First of all, these woofers are among the coolest I've seen. They're not flashy, glossy, or flamboyantly dressed; they're a sophisticated steel-grey with a large silver bullet (phase plug) sticking out of the center. They say, "Just try messing with me." They mean business.

The woofers installed right into the car's factory speaker location

These are some serious-sounding speakers, too, thanks to some of Polk's best design work. The woofers are simultaneously compact, powerful, and accurate. Their size, which allows them to be installed in many vehicles, including my own hard-to-fit Civic, can be attributed to the use of a neodymium magnet structure and an all-in-one basket and magnet cover (with incorporated heat-dissipating "fins"). The neodymium magnet, which is ten times as powerful as a standard magnet and half the size, contributes to the speakers' powerful performance as well. A 1½" voice coil works with the magnet to enable these speakers to handle their rated 125 watts of continuous power (250 watts peak).

The real crowning glory of these woofers, though, is how they manage to be so darn right all the time. With the help of a machine called a Klippel Distortion Analyzer, Polk is able to ensure that the magnet, the voice coil, and the suspension (surround) work together in such a way that the cone's motion forward and backward in response to a signal is exactly the same distance virtually all the time. (They tell me this is more difficult to accomplish than it sounds. From what I've read and the graphs I've seen, I tend to believe them.) This precision in the woofers' construction dramatically reduces distortion. Combine that with the stiff, light aerated polypropylene cone material and a phase plug that improves off-axis performance, and you have a woofer that delivers the punch of a subwoofer and the clarity of a tweeter.

The pièce de résistance

Speaking of tweeters and clarity, the SR tweeters are phenomenally clear. The tweeters are made in a very uncommon design for car speakers: Ring Radiator. The benefit of the Ring Radiator design is that the diaphragm is supported not only at its circumference, but also at the center, and once in the middle, where the voice coil attaches. Chopping the large, single diaphragm up into smaller diaphragm rings not only increases the strength and stiffness of the tweeter, but it also helps prevent unwanted resonance from developing. The phase plug in the center, another feature not found on most tweeters, acts much the same as a phase plug in a woofer: it helps disseminate the sound over a wider area, for more realistic stereo imaging, no matter where you're sitting. I tested this claim out, too. I sat in my car in the four main seating positions and listened to the same track over and over again. In each position, I tried fiddling with the balance and fade to approximate what I call "driver's seat accuracy," but every tweak of the system rang unnatural to my ears. Only when the balance and fade were set to 0 did the speakers sound their fullest and most dynamic, even in the rear seating positions.

Polk uses a "Ring Radiator" design on these high-end tweeters

In fact, the system is so tightly put together that I tried just about every conceivable system tweak — increased and decreased gains on the amp, tweeter boost and attenuation on the crossover, increased bass and treble from the stereo — to see if I could make the components sound just a little bit better, but they produced their best sound when the settings were set to neutral. System adjustments in general, I believe, are expressly for coaxing adequate sound out of less-than-adequate materials. Polk SR series speakers are far more than adequate, so they require little to no adjustment.

Ah, the muuuuuuusic

Due to a glitch in planning, the only CD I had available to me when I completed the installation was the Moulin Rouge soundtrack, which proved to be an excellent selection due to the wide range of musical styles (hip-hop, classical, latin, rock) and the heavy use of orchestra and instrumentals — hence the opportunities for picking out the stereo images. The second track, "Lady Marmalade" by Christina Aguilera, Lil' Kim, Mya, and Pink, swirled around me as I sat in the driver's seat. At the beginning, the vocalists take turns at the stage front mic while the chorus and instruments fill out the crowded stage. Towards the end, the mic moves from artist to artist, left to right, in a spatial relation you must hear to believe. The exceptional richness of the sound made it seem as though I was present at the Moulin Rouge, in the thick of the action. When I played this track later on for my father, who has never cared about musical integrity in his life, he exclaimed "They're so close, I can practically feel them spitting on me." Now, if that's not a ringing endorsement?

I quickly turned to track twelve, "El Tango de Roxanne." This track has a beautiful violin solo at the beginning, rendered with crisp accuracy on the SR speakers, but lacking the overbright, headache-inducing sharpness of many tweeters I've heard. These tweeters are able to reach incredibly high on the audible spectrum without paining my ear, and they do so with such seeming effortlessness that I often forget I'm in a loud, reverberating metal box. That may come as no surprise considering these speakers are adapted from very expensive award-winning home speakers (Polk's LSi series) to accommodate this less-than-ideal listening environment.

The LSi Series home speakers provide the foundation for the Signature Reference Components

Of course, given that I already had images from the movie in my head, I was cheating a little on judging the stereo imaging capacity of these speakers, so I switched to a CD with content not based on a movie I'd seen. I popped in an album called St. Elsewhere by an outfit called Gnarles Barkley. The music might be categorized as hip-hop with heavy soul influences. While the highs were predictably pristine, I was pleasantly surprised by the presence and clarity of the lows. When I was listening to Moulin Rouge, the woofers were just starting to stretch their legs, but they really came alive by the time Gnarles Barkley arrived. The bass and percussion were full, and fully distinguished — no muffled boominess or distant tinniness. The woofers were certainly capable of keeping up with the tweeters in clarity, presence, and depth.

For good measure, I tested some classical music — arguably the most difficult genre of music to reproduce accurately. I chose the Carmina Burana for its full orchestral and choral arrangements and its dramatic mood changes. I was not disappointed. The quieter, chant-like parts were steeped in detail, while the spectacular upswings in pace, volume, and emotion elicited the intended pulse-quickening reaction.

Conclusions

If you've read this article up until this point, you will have heard me extol the many virtues of these speakers — accolades they well deserve. It's true; I think they're as good as any I've heard, better actually. Ask me to find fault, and I have to think hard, but no man-made piece of equipment is without fault, and I'm sad to say that these speakers are no exception.

So, where do they fall behind? Perhaps it's no fault of Polk's that listening at lower volumes significantly decreases the musical detail I heard. It's pretty much a given in a mobile environment that music reproduced below a certain dB level, like 70-80 dB, will be lost to the noise of the engine, the road, the wind, etc. However, I expected these speakers to perform a little better than most speakers on this point, at least on the low end of the frequency spectrum. The highs did fine, but the lows attenuated far earlier than expected. Again, this is only a fraction the fault of Polk's engineers. I have a phone call in to Honda's representatives?

The only other complaint I have is with the unwieldy size of the crossovers. Polk brags about the size of their woofers and how fittable they are, "even in Honda Civics," (from Polk's White Paper on the SR6500) but whatever bulk they took out of the woofers they put into the crossovers. They are close to 7" wide, near 5" deep, and almost 2" tall. That's roughly the size of a hefty novel. While the woofers may fit well in my door, the crossovers don't even come close, so now I have highly visible crossovers sitting in the pockets in my doors, plus a few extra holes. Those of you building competition sound systems may not need to worry about this since you probably won't be trying to hide them. Those of you, like me, who just want exceptional sound for private use, keep this in mind.

The large size of the crossovers makes them hard to conceal in smaller vehicles, but the sound quality more than makes up for it

I really hate to complain about these speakers, though. Polk has a very good reason for making huge crossovers. They are what make the system sound so silky smooth and delectable. The SRs of course are not for everyone — they are meant for the true audio enthusiast, someone who might regard it a cardinal sin to listen to compressed music files. The speakers definitely require an amp, and many would argue that adding a subwoofer is also necessary (though I don't yet have a sub and the bass still kicks), so you're talking about a lot of necessary extra items and a lot of installation time. But if you're prepared to accept these conditions, then get prepared for a stunning sound experience.