Pimping Your Ride with Sony's XM-ZR704 Amp and XS-GTX Speakers

Sony Vehicle, Speakers and Amplifier Overview

It's not often that you get a chance to "pimp" your ride, so when Sony suggested we take a look at their newest ZR Series amplifier and their GTX speakers, we ran out and immediately located a victim, er... test vehicle. The experiment was simple: remove the stock system and replace it with the upgraded amplifier and speakers and note the differences. The proposition was this: would an upgrade of just the speakers make a huge enough difference in a car audio system? Or does it take a complete overhaul. Well, the results were eye-opening to say the least, but we actually ran the experiment both ways (having installed a separate XAV-701HD head unit in a  separate vehicle, while keeping the stock speakers) and this was part 2.

The Test Vehicle

A lot of cars make customization of speakers and head units a real pain, but Toyota is still a beautiful company that doesn't mind people messing with its stock systems. That is particularly true about its Celica vehicles. Ours was a 2000, and with this model it's not only possible to replace and customize the speakers, you can do it behind the door panels with some ingenuity and know-how. Because of the way the vehicle's door panels are constructed, the end result is that your car can look stock, but have upgraded sound that will impress anyone who appreciates good car audio.

The Speakers

So let's take a quick look at the components we're going to install. The front doors will get the XS-GTX1622S, which are 6-1/2" 2-way component speakers. That means that you get both a midrange and a tweeter. In our installation each mid/tweeter system will be fed off a single amplifier channel and the included 12 dB/octave crossover will handle the allocation of frequencies to the tweeter, while keeping the 6-1/2" midrange from having to deal with high frequency material it's not suited for reproducing.

The midrange driver features a Highly Oriented Polyolefine (HOP) material, which is essentially a stiff polymer with a particular geometry for the materials used. And stiffness with light weight materials is what you want in a speaker cone. Sony seems to get this and the material looks to be a quality solution. The 1" Tetron dome tweeter, near as we can tell is made of a soft material similar to a fabric dome tweeter. The magnets on the driver and the tweeter look respectably-sized given the cost and configuration of this system and the crossover allows for a single speaker level input that is then crossed to the woofer and tweeter using a 12 dB/octave crossover slope. The speakers can handle 260W peak power and are designed to take 60W continuous, making them almost perfectly matched for the XM-ZR704 we were installing.

The XS-GTX1642 rear speakers were going in the back and utilize a semi-coaxial 4-way design. It's odd, let's just come out and say it, but basically you have a 6-3/8" woofer, a 1-7/16" balanced dome midrange, a 7/16" dome tweeter and a 11/32" dome super tweeter. It's a little overkill, particularly with how bright these speakers can be, but it seems to get the job done and blows the pants off most "full-range" speakers that lack even two-way fidelity.

The Amplifier

Sony's XM-ZR704 is arguably their top of the line multi-channel automotive audio amplifier. The XM-GS400 is very similar, however it has a smaller chassis and moves the crossover controls to a removable top panel. The ZR704 features 150W of power into 4-ohms, or a more practical 70W x 4 into 4-ohms (which is what you get with the 4-ohm Sony XS-GTX series speakers we installed). Power IS everything with an amp, but Sony also delivered a variable HPF (high-pass filter) and LPF (low-pass filter) for front and rear connections. There is also a subsonic filter that operates at a 12 dB/octave slope and can be configured between 6-70Hz. This is perfect for if you want to make sure your subwoofer is the only speaker handling those super-low, distortion-causing frequencies. If, on the other hand, you're running your own crossover for a passive subwoofer, a 40Hz Low Boost is available to help custom tailor the low frequency shelf response. Oh, and did we mention this amp can drive 2-ohm loads at 80W per channel? This is a very capable amp.

Sony Amplifier and Speakers Installation

Installing the system was fun. We used a myriad of tips and tricks that some people will congratulate on, while others will look down their noses at us. But this is car audio—and if you can't have fun while innovating, what's the point? To get the speakers perfectly mounted within the available space we actually retrofitted some 1/2-inch plywood to use as a mounting bracket. This allowed us to seal the cavity behind the speaker properly, while providing a solid and secure mounting plate for our new speakers. The crossover was able to be nestled into the door panel without running into any areas where it might get tripped up by the window mechanism. We used hook & loop to secure it in place and also provided it with some insulation which served to ensure it wouldn't rattle or introduce mechanical noise to the speaker wire. 

Sony provided ample wiring for the speakers, were we installing them with a feed from the radio. Since we were running new wiring from the trunk-mounted amplifier, however, we opted to go with some high-quality 14/2 cable. For our amplifier power feed sourced from the battery, well... we went a little crazy and got some serious cable that wouldn't heat up under the load, even when driven hard. 

The amplifier mounted easily to the side-wall of the Celica's trunk, offering easy access to the terminals if needed, but keeping it well out of the way when the owner carried supplies or otherwise required the trunk space. Mounting the amplifier is simple thanks to the convenient anchor points located on each corner of the unit. We were impressed by the weight of the amplifier. At nearly 7 lbs., it's no slouch and it feels heavy duty. The glowing blue light on the top may be corny, but it's also very impressive and raises the bar just a little bit when you're showing off the system to friends.

The coaxial rear speakers were a similar installation to the fronts and it took no time at all before we had all 6 speakers (don't forget the tweeters!) installed and hidden behind the factory door panel. It was now time for some listening tests!

Sony Listening Tests, Comparisons and Conclusion

If you remember, our intent was to compare this system against the stock head unit amplification and speakers.  That meant that we had to remember the "before" to compare against the "after".  This is more than a little hard as our brains are truly fickle and tend to remember less than we think they do. I used a few key tracks and took ample notes to help, as much as possible, my recall as I plodded forward with my experiment.

For starters, the head unit was acceptable and not the $5 stock unit that came with the vehicle, so we weren't exactly starting with a poor source device. The factory speakers, however, were—as you might expect—atrocious. When we started out listening tests we used the JVC KW-R500 to drive the factory speakers. On Dire Straits "Money for Nothing", the tone of the guitars (pre-upgrade) had none of the crispness that I've heard on more equipped systems. The stereo effect of the guitars following the intro was also not nearly as impressive. It wasn't mono, but it was close. When we went back with the installed and upgraded Sony system the difference was palpable—literally, we felt it. The snare had a much more "sure" strike and the stereo separation was pristine. While the placement of your head in the vehicle affected the separation (as you might expect) the effect was much more authentic and lifelike—almost as if you were listening to an intimate presentation by the band.

We also want to displease that we did some tweaking of the system post-installation. For one, it was a tad bright. As with many car audio systems, the difference between what you are used to and what you get following an upgrade can be quite startling. You don't want to assume a system is "bright" simply because you're finally hearing all those frequencies you thought never actually existed! In this case, however, we used the head unit's Pro EQ (a parametric equalizer) to dial down the output around 10kHz just slightly so as to smooth out the response a little bit and remove some of the perceived harshness.

Turning to the bass response, we queued up Seal's "Waiting for You" from his Seal IV album. Right off the bat there is a steady, punchy synthetic bass line that doesn't let up for the entire track. The Sony XS-GTX speakers handled it with an impressive dynamic range. While a subwoofer would have made this track all that much more impressive, it was far more dynamic than we experienced pre-upgrade. Bass was tactile enough to be impressive and it wasn't overblown. And with this track, you can instantly tell if a system has a ridiculous bass emphasis—because the bass line is already naturally bloated just a bit (if it tips the scale, you know it's the system).

We did a ton more listening, but one of our final tests was James Taylor's "Don't Let Me Be Lonely Tonight". James' vocals played through with a very natural and authentic tone—which is how you WANT James to sound (anything else is just plain wrong). His guitar was equally well-presented as was the accompaniment. Stereo separation was excellent, and the bass guitar was both smooth and punctuated, and it conveyed a very natural decay. James' tenor voice really pushed the midrange on this system and it performed admirably. This is an album that, to me, epitomizes the male tenor vocal range. Get this right and you've got a pretty decent speaker.

Conclusion

For a grand total of around $350, this is a system that will provide an incredible upgrade for your vehicle. As a  fellow audioholic I feel it my duty to ensure that our readers at least consider extending their hobby to their cars. I have gotten to a place now where I absolutely hate getting into a car and continuing a song I was listening to in the home—on a much more equipped system—only to encounter a distorted mess in my vehicle.  It doesn't need to be that way, particularly with affordable audio systems like this from Sony and other companies. Sony and others update their systems pretty regularly, so don't be surprised if the model numbers in this review become obsolete or change over time. We'll try to keep up when possible, but while the feature sets might change it's more than a little likely that speakers and amplifiers in the same series and made with similar materials will carry a very similar tone and performance. As always, we recommend you demo these products at a local dealer whenever possible. As for me, I'm going to go listen to some music...this time in my own car.

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

• — Excellent
• — Very Good
• — Good
• — Fair
• — Poor

Metric	Rating
Build Quality
Appearance
Treble Extension
Treble Smoothness
Midrange Accuracy
Bass Extension
Imaging
Soundstage
Dynamic Range
Fit and Finish
Performance
Value