[Review]Subwoofer Comparison Test

[Aaron Clinton 2,372]

Subwoofer Comparison Test: Round 3

By Vance Dickason

Photography: Rob Mcpherson

As in amateur boxing, this is the third and final round of the Subwoofer Comparison Test. This time we feature four speakers in the highest price category, $499 and up. No knock-outs or TKOs but certainly there are winners in our series of tests. But you are the judges and make the final determination. In the end, context is king. The woofer that is best is the one that is best for you.

Objective: Four Max Performance Long Excursion 12" Woofers

In the first round of the Subwoofer Comparison test we looked at four woofers that had price tags from $270-$300, followed by the second group that ranged from $309-$499. This month's selection includes four woofers with prices from $499-$799. These "heavyweights" (all of these woofers weigh between 29-38 lbs. each!) include the Crystal Mobile Sound CMPx212, the Fujitsu Ten Eclipse 88120Ti, the Kove Audio Armageddon Z-12 and the Massive Audio DMx12.

Like the previous sets of woofers I have examined, this group has some qualifications. First, the price spread for this lineup is about $300. Both the Kove and Massive woofers are priced the same $699 and $799 for the Eclipse, with the CMPx212 coming in at a mere $499. Despite this much difference, performance was fairly similar for all the woofers regardless of price. Like the first group, three of the woofers submitted have dual voice coils and one woofer with a single coil. This isn't really a problem as long as you keep in mind that the big difference between dual and single voice coil woofers is that it takes less voltage to drive a lower impedance dual voice coil woofer (when driven in parallel) to the same SPL levels as a higher impedance single voice coil woofer.

The other similarity worth noting is that all the woofers have rather low Vas numbers, which means they are capable of working into very small enclosures. However, two of the manufacturers recommend sealed and vented boxes (Kove recommends ported, Eclipse, sealed; more on that later) that were much larger than the numbers would indicate. The reason for this is that woofers in this category have tremendous power handling capabilities and are pretty much expected to be played at very high SPL levels (hey, no one is going to spend $700 on a subwoofer to play elevator music while cruising). At high SPL's the voice coils get very hot and the impedance increases to the point where the parameters are then more suitable for the larger box. In terms of vented boxes, it's almost impossible to create a vent for a small vented box that will move enough air to be satisfactory, so if you want performance, it's a larger box or nothing.

Testing was done using the same procedures as the previous subwoofer tests (this way you can compare results from review to review). The LinearX LMS analyzer (with the Win9X software) was used in conjunction with the LinearX VIBox to produce separate voltage and current curves (also called admittance curves) in a 10 Hz-10 kHz frequency range with a 550-point sweep resolution.

Using "Ohms Law," these two curves were then mathematically divided (V/I=Z) and the data converted from voltage to Ohms to produce high-resolution impedance curves. This data was then imported into the LinearX LEAP CAD program (a Win9X version of LEAP is due out in a few months). Once the LMS data was loaded into the LEAP software, box simulations were created at 2.83V and at a voltage level high enough to produce cone excursion that was equal to the Xmax of the voice coil plus about 15%. This method describes the woofer's linear operating envelope, which approximates how loud the woofer will get before it starts creating noticeable distortion.

Crystal Mobilesound CMPx212

Crystal Mobilesound has been a player in the car speaker business for over 10 years. While the vast majority of speaker manufacturers in the industry buy their drivers from large OEMs (sometimes doing their own engineering, sometimes not), Crystal Mobilesound is among the few that actually build their own woofers (for more about Crystal Mobilesound, visit their Web site at www.crystalmobilesound.com). This applies only to subwoofers, however, as Crystal buys its small drivers such as coax and component products from a driver OEM like most of the other speaker companies. But whether a manufacturer builds a woofer in his own factory or has it done by a competent OEM factory, what counts is the engineering that goes into the product. If the recipe is a good one, it doesn't much matter who does the cooking.

Built on a cast aluminum frame, the CMPx212 combines a tasty list of features, as you would expect from any $499 car sub. The cone assembly employs a somewhat unique cone that may look like a standard paper cone, but is actually a honeycombed Kevlar mixture that is extremely stiff, the right choice for a high powered sub cone. Crystal actually makes this cone in-house, which is unusual since even manufacturers who build their own woofers generally buy all the parts from speaker parts OEMs (the next level back from the OEM driver makers). The cone is terminated on the inside diameter by an injection molded (with a slick 3-D CMP logo) inverted 5.5" diameter dustcap.

This Kevlar/paper composite cone is attached to the frame using a 1" wide Santoprene heat formed surround. The same material is used to form the mounting gasket "boot" that acts both as a rear sealing gasket and a front mounting gasket. A 7" diameter three-layer flat cloth type progressive spider (progressive means that the spider gets increasingly stiff at the extremes of excursion and is generally used in speakers intended for vented box designs) that has the voice coil lead wires woven into the surface of the spider supplies remaining compliance. Having the voice coil lead wires woven into the spider is becoming rather popular with manufacturers of car subs. Voice lead wires woven into the spider cloth certainly ends the worry about the voice coil leads bouncing off the cone during high excursions, which can be audibly distracting.

Cone, surround and spider are attached to a 3" diameter dual winding voice coil. Each coil has a 2-ohm DCR (the resistance when using the direct current method) so running this driver with both voice coils connected in parallel means a 1-ohm load, no problem for the present generation of high current 12V amplifiers (I wouldn't hook one of these up to your home theater receiver, however). Although the CMPx212 uses a very thick front plate like an underhung configuration woofer, the voice coil is actually longer than the gap making this a overhung type of motor.

Both coils are wound on a black anodized aluminum voice coil former (the black color enhances heat dissipation). The lead wires are connected to gold-plated push terminals located on opposite sides of the driver frame. The frame itself is a black painted cast aluminum type whose main feature is a 33 mm depth below the mounting plate that allows for the substantial rear excursion of the spider.

The motor structure also combines some interesting features. Two stacked 25 mm thick 190 mm-diameter ceramic ferrite magnets supply magnetic energy for this motor. The milled, polished, plated and tapered 33 mm front plate and a likewise milled plated and polished back plate complete the magnetic circuit. While the thick front plate is unique, the 15 mm back plate for the CMPx212 also has some interesting features. First of all, as with most high quality subwoofers currently on the market, the back plate is the T-yoke type that combines both the back plate and the pole piece into a single structure. The interesting design aspect however is in the vertical part of the T-yoke, the "T", which has eight 1/16" grooves on the inside of the pole vent. According to the Crystal Mobilesound engineers, the multiple grooves increase the heat dissipating ability of the woofer motor. Besides the heat dissipation "tricks," the pole piece is an undercut T, shaped and extended to help increase the linearity of the magnetic fringe field in the forward moving direction. The extension is also hollowed out to decrease losses in magnetic flux. Adding to the heat sink mass of the motor is a 10 mm bumpout extension with a 1.5" pole vent for cooling.

Eclipse 88120Ti

Fujitsu Ten is not a newcomer to car audio. The U.S. division recently celebrated their 25th anniversary in August 2001. In 1976 when they started the American operation, car audio was just beginning to take off. The Eclipse brand, however, didn't come into being until 1989 (see the company Web site at www.eclipse-web.com). Like the previously reviewed Eclipse 88150Ti, the 12" version, the 88120Ti has some impressive features, especially the single piece titanium cone. The entire line of "Professional Subwoofers" features a really great looking titanium cone that is stamped and spun out of solid titanium. After machining, these parabolic shaped single pieces (no dustcap) cones are chemically treated to prevent oxidation, the logo etched across the center, and a clear coat of lacquer applied. The end result is a very highly polished cone that looks more like it's been chrome-plated (instead of raw titanium). Fujitsu Ten's 12" 88120-Ti DVC subwoofer combines most of the state-of-the-art features that are expected in a high performance competition grade woofer. The silver painted cast aluminum frame is a carefully thought out design that is configured to accommodate the long excursion capability of this device. This design includes six large "windows" with metal screens below the spider mounting level that enhance heat dissipation. In order to facilitate the dual mirror imaged 9.5" diameter spiders (one spider is turned upside down so that the first fold is going upward on the top spider and downward on the bottom spider), a high-temp plastic standoff provides the support for the top spider.

The motor structure combines a machined and highly polished T-yoke back plate/pole piece combination that was designed using HiMarc Simulation's Opera FEA (Finite Element Analysis) magnetic field simulation program. The pole vent is shaped to accelerate the air passing though the vent using the "venturi" principle (kind of like an airfoil on the wing of an airplane or the throat of a carburetor) and is called the "Aero Vent" in the company literature. The opening at the top of the gap is over 2" and tapers to 1-3/8" at the exhaust end and also includes a 15.2 mm pole extension to linearize the fringe field above the gap. Like the T-yoke, the front plate is also an interesting design. From the outside of the woofer the front plate appears to be a standard 11 mm thick plate, but it has an elevated portion near the gap area that forms a gap height of 35.56 mm. The advantage of this configuration is that it allows for an extremely large gap height with significantly less metal for the magnet to "drive." If this front plate were 35.56 mm thick throughout the entire radius it would not only make the woofer substantially heavier (and even more expensive), but would decrease the available magnetic flux to power the motor system due to losses. It is interesting to note that even though very large gaps are characteristic of underhung (large gap/short voice coil), this woofer, like the Crystal Mobilesound CMPx212 , uses the more common overhung configuration. Magnetic "power" for the 88120Ti is provided by three stacked 190 mm x20 mm (7.48" x 2.36") magnets to produce the roughly 9 Tesla Meters of Bl required to power the 12" machined titanium cone. The motor is finished off with a black rubber "boot."

Fujitsu Ten's cone design follows the still current trend toward dustcapless single piece "bowl" shaped cones. The concave parabolic shape provides exceptional rigidity further enhancing the overall stiffness of the metal. To provide better dimensional stability at the periphery of the single piece cone, the cone rim is bent at 90 degrees forming a reinforcing rib and works in conjunction with another corrugation just below the surround attachment point to keep the outer edge of the cone from deforming. The 4-layer voice coil is wound on a 3-inch aluminum former attached with thermal conducting epoxy to the base of the cone. This results in a massive heatsink that provides an unusually efficient heat conduction path from the voice coil into the heat conducting 12" titanium cone. Like the Alumapro metal cones subs, the heat dissipating ability of this format is very impressive.

The 88120-Ti's suspension system combines a 2" wide positive roll Polyether foam surround with dual 7.5" diameter flat polycotton spiders. Since the 88120Ti was designed primarily for sealed box use, the company chose to use a linear suspension system rather than a progressive suspension. However, this low compliance woofer will work in both vented and sealed; and the company hands out box recommendations for both types. Last, the dual 3-ohm voice coils are terminated to silver-plated cadmium conex core tinsel wires that are woven into the top spider and connected by a pair of color-coded chrome-plated spring-loaded terminals.

Kove Audio Armageddon Z-12

Kove Audio was founded fairly recently in 1997, but the company owners have been in the car audio business for over 27 years, having founded at least one other well known company. With an imposing name like "Armageddon," the Z-12 was an all-out project for Kove, with Gary Kovner's instructions to his chief engineer to build the best woofer possible, and never mind the cost (for more about Kove Audio, visit www.koveaudio.com).

The Z-12 is built on a cast aluminum frame that has a substantial 40 mm (1-9/16") of reward travel for the spider (this includes a sizeable mounting ring for the spider), painted with a good looking grey wrinkle finish. The motor structure for this woofer features dual stacked 190 mm x 25 mm ceramic Y33 ferrite magnets sandwiched between some very serious metal. The front plate has been milled and polished and finished in a black coating to increase its heat dissipation ability (the black body radiation effect). The back plate is a CNC machined T-yoke (pole piece and back plate are a single piece of metal) that has been milled and polished with the Kove logo engraved on the back, but without the black coating. Magnets and plates are covered by a black rubber magnet "boot." Like most woofers in this class, the pole piece includes a 10 mm extension to improve the linearity of the forward magnetic fringe field. For cooling, the pole has a 35 mm (1-3/8") diameter vent with radiused edges to prevent turbulence noise and improve air flow. Incidentally, the engineers at Kove use all my favorite tools for design, LEAP, LMS and SpeaD (SpeaD is a fairly new program from Red Rock Acoustics that allows a speaker engineer to input the specifications of all the parts in a woofer and have the program give the T/S parameters).

The cone assembly for the Z-12 is also impressive. Subwoofers that handle this much power need very stiff cones, and the Z-12 achieves this with a thick-coated fibrous pulp (paper) cone with a integrated Kevlar mix. Finishing off the cone is a 4.75" diameter, heat-formed 3-D concave shaped dustcap. Connecting the cone to the frame, Kove used a dual density heat pressed foam surround that measures about 35 mm wide and 21 mm high. Kove uses a black Santoprene mounting gasket that covers both the front and rear of the frame mounting area.

Remaining compliance is provided by a pair of black 7.125" diameter poly-cotton blend progressive spiders. Kove primarily intended this high powered sub to be used in vented enclosures, hence the progressive spider (the two spiders are mounted in reverse direction back to back). While the woofer will work into a sealed box, and I did include simulation of this woofer in a sealed box just for comparison purposes, its stiff progressive suspension causes a fairly high rolloff. Still, it is capable of producing tremendous SPL. Like the other three woofers in this review, the Kove uses the new type of spider with the tinsel leads woven into the body of the spider. Industry consensus seems to be that this is definitely a superior way to handle the tinsel-to-connector path. The tinsel leads are terminated to a single set of color-coded chrome push terminal designed to accommodate large wire gauges. All parts in the cone assembly are held together with a high temperature "aerospace" epoxy. The shuttle doesn't fly apart and neither will this woofer!

Powering the cone assembly is a 3" diameter voice coil wound with aluminum round wire onto a black anodized aluminum former. Using the aluminum wire cuts the assembly weight giving the woofer greater sensitivity and acceleration. As mentioned in the beginning of the review, this woofer uses a single 4-layer voice coil, so it has a DCR roughly twice that of the other three DVC woofers. When looking at the comparison data chart, keep in mind that the other woofers take less voltage for a given output because both coils are parallel driven in the simulation.

Massive Audio DMx-12

Massive Audio is a fairly new name to car audio and was introduced about two years ago. However the parent company has been in the pro audio speaker business for about 14 years, which is good experience if you want to build high power car audio subs and component systems. The model submitted for this review is the new DMX-12. This model represents the first in Massive's new high performance DMX line of subwoofers and speakers. You can find out more about Massive Audio at www.massiveaudio.com.

The DMX-12 long excursion subwoofer is built on a new frame for Massive. This cast aluminum black painted frame has 12 narrow support "spokes" and 12 vents below the spider for cooling. I've never seen this frame used before, and it really is a well-designed frame for both mechanical support of large heavy motor structures and cooling across the front plate. There is a substantial 45 mm (1.75") from the spider mounting shelf (a plastic mounting ring is used to support the spider).

The motor structure is built around dual stacked 190 mm x 25 mm ferrite (Ceramic 5) magnets. Holding these to the frame are a set of machined plates. Both front and back plates are machined and coated with a black emissive coating to improve heat transfer (if you remember high school physics, then you know about Planck's Constant [h] and the black body radiation effect and how it was the first step in the field of quantum mechanics?). The back plate is a single piece T-yoke type with a chamfered top that reduces magnetic losses and maximizes air flow from the pole vent. The pole vent is 35 mm (1-3/8") diameter with a radiused exhaust hole to improve air flow and decrease noise. Along with the hollow pole piece vent, the pole is extended above the front plate by 5 mm, again to help linearize the magnetic fringe field in the forward moving direction of the cone assembly, and to improve cooling around the voice coil. Pole piece extensions also act to provide a path guide for the voice coil on extreme excursions. Finishing off the motor system cosmetic is the customary black rubber magnet cover.

Like the Z-12 and the CMPx212, the DMX-12 uses a fibrous pulp cone (paper) that has had Kevlar fibers added to the slurry to increase the stiffness. Obviously, this type of composite cone is pretty popular with manufacturers and this is due to its light weight and stiffness, an all around good performer that's hard to beat. The dustcap is a 4.75" diameter concave injection molded type with a 3-D Massive logo. Connecting the surround to the frame is a vacuum-formed Santoprene surround (Santoprene is a great material for surrounds, less expensive than rubber, but with most of the good edge damping characteristics, and better long term stability than foam) that measures 37 mm wide and 21 mm tall. Massive uses a black Santoprene mounting gasket that covers both the front and rear of the frame mounting area.

The remaining compliance is provided by a 7.125" diameter dual black poly-cotton blend spider arrangement. These linear configured spiders have their roll geometry reversed to cancel out odd-order non-linearity's (trust me, it just works better than one spider alone). Like the other three woofers in this review, the tinsel leads are stitched into the body of the spider.

Driving the DMX-12s cone assembly is a 3" diameter, dual 2-layer winding voice coil (4 layers total) that uses aluminum wire wound on a black anodized 5 mil thick aluminum former. The black adds to the heat dissipating ability of the voice coil and the aluminum wire makes for a lighter assembly for greater overall sensitivity.

After reading all the woofer descriptions you would probably guess that the comparison of these four woofers represents a fairly level playing field, and you would be right. Looking at the data chart pretty much tells the story. If you look at the T/S specs for these woofers, the CMPx212 has the lowest Qts and the Eclipse the highest. However, the range is such that they are can be placed in both vented and sealed enclosures. Starting with the sealed box computer box simulation the first thing I noticed (see the introduction) was that each of these manufactures recommends box volumes considerably greater than you might get from the numbers and a calculator. I decided to follow my usual procedure and first compare all four woofers (again, remembering that Kove does not recommend their woofer for sealed boxes) in the same Qtc=0.7 (box "Q") design, which means for this group, four different sealed box volumes ranging from 0.25 to 0.7 cubic ft. As can be seen, this also means box volumes so small you couldn't build a box that would be both this volume and deep enough to mount the woofer inside of it. Despite that little problem, the comparison shows the only woofer that really has much low-end performance in a small sealed box is the Eclipse 88120Ti, but even they don't recommend a box this small. The second box volume I used was 1 cubic ft. for all four woofers. The results showed the CMPx212 to have a very low Qtc (box "Q") and the Kove a very high F3 (and also the highest linear SPL). However, all four box Qtc's were low (over damped); but as I said in the beginning, once these bad boys warm up, the Qtc's will come up considerably, so it's not so much of an issue unless you listen at maybe 80 dB and never louder (but, then you probably wouldn't be reading this magazine).

Next I did computer simulations in a 1.75 cubic ft. vented box. Here, the playing field was much more level. While the box tuning had to be adjusted to work with the individual driver parameter sets, all but the CMPx212 were in the 30 Hz range; so they were at least similar in this respect. All four woofers produced F3's in the vicinity of 30 Hz with the CMPx212 having the lowest rolloff at 22.5 Hz. It terms of maximum linear output, Kove at 120 dB walked away with that honor, but not really significantly in terms of what I hope is reality for users of these products. All four of these woofers are easily capable of SPL's that exceed 110 dB without any hint of distortion, which means you'll be messing up your hearing before the woofer gives out. About the only place the high SPL number might count is in a dB Drag type of competition, and even then, a lot of other factors are involved to make a winning design, not just the absolute numbers in the data chart. You should also be aware that these numbers are computer simulations based on sine wave analysis and that the actual level before the onset of distortion depends significantly on the program material content. Figures could be as much as 3-4 dB higher or several dB lower depending on conditions.

Bottom line, I don't see any clear standout winners in this group, they all appear to be great performers and at this price range, all have extremely nice build quality. If space was a problem and you really wanted to use a small sealed enclosure of some kind, the Eclipse is probably the best choice. However, this excludes the most important judgement to be made, the subjective one. So how do they sound? Ask Tim.

Subjective

The final round of the long excursion, 12" subwoofer test is literally the battle of the heavy weights. The "lightest" of these four subs weighs in at nearly 30 pounds. Hauling the woofers and enclosures in and out of my Toyota Tacoma ExtraCab nearly required a small forklift.

While the second round featured subs in the $300-500 range, the latest woofers will set you back as much as $800 each! Power handling took a jump too, with the highest peak rating of 3500 watts. That's some serious power. To make sure I could shock every coil in this test, I stepped up my amplifier.

To the top of the food chain. Rockford Fosgate's hot new Power BD1500.1 was the power source for this test. To make sure the amp had enough current to hit the more than 1700 watts its birth certificate showed it was capable of, I also added a second battery and mounted it within 18 inches of the amplifier. Just like the last test, there were no problems with the Rockford amp and I'm certain it pushed these subs for all they're worth.

Keeping in mind you buyers, I used the same music selections for consistency as in round two with the exception of substituting Outkast's "Stankonia" for Ludicris' "Back For The First Time." This was just a little change in pace. Like last time, I weighted it more than any of the others because this is likely the most popular type music for someone purchasing these subs.

For Techno or Dance I used Yello's "Baby." While many of you may not recognize them, you may remember their track, "Oh Yeah" from "Ferris Bueller's Day Off." All the music is synthesized but very complex and very well arranged. I used track 3, "Rubberband Man" because it has a synth bass line that moves like a staccato march through different frequencies.

For rock I used Nirvana's "Nevermind," track 5 "Lithium." The recording on this album is much better than anyone ever gave it credit for and the song starts with a high impact kick drum matched by bass guitar. It was basically a sound quality and impact check.

Radio is back, too. While you can't compare the same song with every woofer, KISS FM here in Phoenix as well as Los Angeles and Las Vegas, plays popular music and heavily boosts the bass for the average Joe who's only got a factory system. Listening to a track on the radio and then the same track on CD will give dramatically different results. Turns out people listen to the radio quite a bit so, like the Outkast track, it gets extra weighting.

Last, I got a recommendation from someone who used to make a living with his ears: a pair of tracks completely unknown to me previously AND in a different language. With that combination, you're forced to listen to music. You don't know the rhythm or the lyrics so your mind can only concentrate on the tone and pitch.

First was Cheb Mami's "Meli Meli." Turkish Pop sung in Arabic is about as good as I can describe it. Again this is synthesized music, but Cheb has an excellent voice and track 4, "Parisien du Nord," is like listening to rap in another language. Second was Salif Keita's "Folon." Track 2, "Mandjou," has a very smooth bass drum and bass guitar about a half beat apart. I used this track as a sound quality check.

That does it for the music selections. When it came time to build the enclosure, not a lot of effort was put forth. You see, each of the boxes built are simply manufacturer recommended enclosures for each subwoofer. The box volumes were calculated and built as to what is printed in the manual, online, or recommended by the tech departments. This seemed appropriate -- so that I can convey my opinions based on the box that someone purchasing one of these subs would likely build. Each of these enclosures were then placed into the vehicle, one at a time, with the woofer facing the right side of the rear compartment. Each was placed the same distance from the right side wall.

In testing these heavyweights, only minor adjustments were made to match the woofer to the rest of the system. The adjustments I am speaking of are the crossover and input gain control on the Rockford Fosgate BD1500.1. No other processing was placed into the system, nor was the bass or loudness adjusted from the neutral or off positions.

A final note about the ratings. The ratings were given in a way to indicate that one of the four subs did it better than the rest, not to some esoteric standard only known to me. That's why there is a perfect score in every category. Another sub not in the test may do better, but since I don't have my hands on them, it doesn't count.

Eclipse 88120TiDVC

This was the most expensive and probably the most incredible looking woofer of the four. It's made from a real titanium cone and has a skyscraper tall motor structure. The voice coil is so overhung that you can see the coil windings extend past the top of the magnet stack. The 88120TiDVC was the only sealed box sub in this test. The box was big by comparison to the second round of tests, but plenty reasonable for a true SPL woofer. At 1.75 cubic feet it wasn't too much to handle.

After listening to the 88120TiDVC it was pretty easy to see that this is a purpose built sub. A titanium cone, gigantic surround and a motor built to take pubescent abuse add up to a sub that belts out SPL and bumpin' tunes to be heard for blocks. The flip side is that it doesn't do well at anything approaching sound quality. But Lamborghini's aren't known for their plush ride and luggage space. Same rules apply here.

On Yello's "Rubberband Man," there was lots of output, but the 88120TiDVC never really got the cascading bass notes to come through clearly. The same on Salif's album. The bass drum had good impact, but there was too much overhang.

Switch it then to the racetrack and things change. On the radio, this sub was at home. Tons of boosted output, 60-80 Hz bass. Same for Outkast's track #8, "Spaghetti Junction." Bump, bump, bump. The synthesized notes of Cheb Mami came through with the impact needed to beat up a bit. The Eclipse 88120TiDVC is a monster. It's meant to be used for long excursion, super high power SPL systems where the owner is not looking for a compromise between sound quality and output. It's also expensive, but these kinds of materials don't come cheap.

Massive Audio DMx12

The Massive Audio DMx12 was wedged into a 2.67 cubic ft. vented enclosure. That's closing in on the box size for sealed 15-inch sub, but like Vance explained, when these subs get warmed up, their parameters change and, at least for high SPL, they'll work better in larger boxes.

Once it was inserted and the front seat put back in place, I cranked up the DMx12. I wasn't disappointed. First try was the Outkast track and it immediately loosened some fillings in my teeth. Better, it was even fairly clear and fast. Some overhang was apparent on certain notes, but this thing is obviously purpose built for extremely high output.

Yello's "Rubberband Man" put plenty of output in the cabin, though it didn't quite get every step on the cascading bass march. What it did though was hit the low notes. I was pleasantly surprised with the box tuned in the mid thirties how well the low bass extended.

Same thing for the radio. Not only was it getting the low bass, but it was fairly tight from note to note. This is pretty hard to do because the radio stations add a bump to the airwaves to help cheap OEM speakers.

Switching to rock and Nirvana's "Lithium," the bass drum hit right on even at make-sure-you-have-headphones levels. There was a bit of trouble when the bass guitar was playing a half note off the kick drum, but all around it was good.

[Aaron Clinton 2,372]

On Cheb Mami, the synth bass was thumping along but higher frequencies were shallow. Adjusting the BD1500.1's crossover didn't help things. The bass line on Salif's "Folon" is the psydo sound quality check; and while better than the Eclipse or the Kove, sound quality may not be this woofer's calling.

The basket of the Massive Audio DMx12 was unique, though its back plate was just plain black for heat reasons. On SPL tests, the Massive Audio DMx12 was hitting big, running the Rockford Fosgate amp for all it was worth. Take a look here for an SPL hitter.

Kove Z-12

Of all the subwoofers in this test, the Z-12 is the only one that is recommended to be used only in a vented box. As well, a large, square port is suggested for high power applications. So that's exactly what was cooked up - a 2.7 cubic ft. box with a square vent. Like the Massive, I had to pop out the passenger seat to get the box in the extra cab.

As the only single voice coil woofer in the test, the Kove was at a disadvantage because of its nominal 4-ohm rating. Max power from the Rockford Fosgate amp comes at 2 ohms, but the 1500.1 was certainly able to run the Kove at its 750 watt continuous rating.

Starting with sound quality and the "Folon" track from Salif Keita, the Kove was a little flat. The kick drum beats kind of ran into each other with audible overhang. Same for the Nirvana track, but output was better.

A switch to bumpy bass was in order. Turn on the radio. Now you're talking. Instantly the Kove came alive. A turn of the volume knob to the right and everything in the truck was vibrating.

The Kove was at its best, however, on the Outkast CD. "Spaghetti Junction" worked so well that I was encouraged to sample other tracks. The whole mix on the "Stankonia" just seemed to suit the Kove. The only thing I wished for was a dual voice coil version of the Z-12 in order to achieve a 2-ohm load and work the BD1500.1 for everything its got.

The Kove Z-12 excels at big boomy bass. It will do some regular listening and is pleasant at low levels, but you're best to just know that this woofer was meant to thump.

Crystal Mobile Sound CMPx2 12

This is kind of the dark horse of the bunch. At $499, it's the least expensive of four very expensive woofers. Oddly enough, the CMPx2 12 is the heaviest by far. Visually, it appeared to have the smallest surround of the bunch (though it is still huge) and a machined top plate and t-yoke that get good visual marks.

The CMPx2 12 got stuffed into a 1.7 cubic ft. vented box for our tests. This is a very reasonable size for a ported enclosure. The port recommended was four inches in diameter, possibly a little small for a woofer that is capable of moving massive amounts of air. To my surprise, no vent noise was noticed during our test.

First track through was Salif's "Folon." The CMPx2 12 initially seemed a good match for the Massive in terms of sound quality. Things were fairly tight with considerably less overhang than any of the other three. But with such a low tuning frequency, you should almost expect this. Switching to Nirvana, things got even better. The bass and the kick drum were distinct and had great impact, though I wished for a little more SPL here at mid and low volumes. I found it on Cheb Mami. Here the synthesized bass notes were pumping the sub to big excursion levels with some overlap of the high bass notes.

On Yello's "Rubberband Man," the CMPx2 12 got the best results of the bunch at accurately hitting the cascading frequencies of bass notes. Again, output was a bit shallow at low volumes, but from a musical standpoint, the response was exceptional.

Like the Kove woofer, the Outkast CD produced the best results with the CMPx2 12. In the first 30 seconds of the CD there is a repeating bass line that, as it turns out, changes frequencies. None of the other woofers were able to reveal this, but right off, with the Crystal CMPx2 12, I could hear the bass note change frequency midway through. You know a speaker is doing its job when it reveals things others do not.

While the output at mid and low volumes may have lagged slightly, the CMPx2 12 was able to produce some serious sound quality. The Crystal is likely on the same level as the Earthquake and the Crossfire subs from the previous tests in sound quality, yet with a bit more output.

All Told

After all the testing was done it was simple to draw a few conclusions. For the most part, all of these subs are purpose built. They're like dragsters, dB dragsters. Forget about sound quality. The only one to hit a home run in that ballpark was the Crystal CMPx2 12.

Each of these heavyweights is big and expensive. You had better be dedicated before buying a few of these subs -- or have a lot of credit on your card. You're also going to need a serious system to build around them. Big amps, high current power delivery system and a fairly large box.

This group was the best matched of the three tests. They all fit the SPL bill and they all could take a serious beating from one of the biggest amps in the industry. The Eclipse seemed to suffer somewhat from its fairly small cone, while the Crystal, Kove and Massive woofers were pretty much an equal match, but only when you played them with big bumping bass music -- forget the rest.

Save your pennies boys and girls because all these subs mean business and a small farm of them will cost you as much as a winning scratcher ticket.

[Tirefryr 1,742]

That was awesome. Got any more?!

[Aaron Clinton 2,372]

I can search around for some

[Tirefryr 1,742]

Sweet. Those are awesome! Makes me wish I never got rid of all my old audio magazines.

[Mark 0]

Ah what does Vance know about speakers?

Nuthin'! I wipe my butt with his book

..that's not true at all.