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Phase Technology WL-12 Subwoofer Review​

The subject of this review is the Phase Technology PC SUB WL-12 subwoofer. The WL-12 has a down firing 12" driver with a front firing 12" passive radiator (PR). Measuring in at a mere 16.5"x15.25"x14.75" (HWD, at it's widest point), and weighing 41 pounds, it's certainly not a large or particularly heavy subwoofer. The internal amp is rated at 300 watts RMS, 900 watts peak. The quoted frequency response is 22Hz-200Hz. There is a very generous 10 year warranty on the speaker and 3 year warranty on the amp, which is quite a bit more then most companies are providing today. The WL-12 retails for $1560.

Phase Technology has been in business for a really long time, starting in 1955 as United Speaker Systems. I can't think of too many other audio companies with that type of history. All Phase Technology speakers and subs are designed, engineered and manufactured in the US. That's a very laudable trait, and extremely rare these days.

The unit came single boxed, which isn't ideal given how packages seem to be treated these days. The sub was protected on the top and bottom with a thick piece of pliable foam, custom cut to fit the unique shape of the cabinet. The subwoofer itself was wrapped in a foam sheet. I consider this to be about the minimum protection for shipping a subwoofer these days.

The manual is small but decent. It's well laid out and contains just the essentials. It details three different models, not just the WL-12. Accessories include the power cord -- which is 2 prong, so there should be no issue with ground loop noise -- as well as stick on pads for the rubber feet when the sub is used on hard surfaces. There's also what is arguably the most significant feature of the WL-12; a wireless transmitter. This small box attaches to the sub-out on your AVR, which then allows you to place the subwoofer just about any place your heart desires. The receiver is already built into the amp, so there's nothing else to hook up. It transmits in an uncompressed format, meaning you loose nothing by using wireless over wired.

Initial Impressions
The WL-12 is a very small subwoofer, so it's not going to dominate any room. The review unit had an attractive cheery veneer finish, which was a nice change from the typical gloss/satin/matte black of most other sub's. It does come in black too, so if you're interested in a more traditional look Phase Technology has you covered. The cabinet has a gentle curve to the side panels, which gives it a stylish appearance. The knuckle rap test returned a fairly solid sound.

The front and bottom panels are 1.5" MDF, while the rest of the cabinet is constructed of .75" MDF. There's a horizontal support brace attached to the middle of both side panels that runs their full length. Couple that with the curved sides and on paper it would certainly appear as though Phase Technology has accounted for virtually everything to ensure a solid structure, but even with all that I did notice a tendency for the cabinet to show the effects during intense bass passages. By that I mean if you placed something on top of the cabinet while it was working hard you would often find it moved around, indicating that it's not completely inert.

The entire inside of the cabinet is lined with 1" thick fiberglass batting. The top sheet on the review unit had come loose and was laying on the driver. To rectify that I simply used a little aerosol adhesive and put it back in place. I found out later why that may have happened; turns out I had serial number 3 -- yes, that's right, 3 -- which was not a production model. After speaking with Ken Hecht, the president of Phase Technology, I was informed this particular unit was not one I should have gotten, and was actually shipped in error. According to Ken the true production units differ in just a few areas, so the review unit is pretty much identical to what a person would receive were they to purchase one now. I never did quite figured out how I got a pre-production unit though, because it appears the WL-12 has been out for several years.

In the interest of full disclosure... while doing my review I noticed what sounded like an air leak during deep and/or loud bass passages. Most often it was only noticeable when you were close to the unit, but there were actually a few instances where it was audible at my primary listening position. I spoke with Ken about it and he suggested I send the unit back for evaluation. It was at this point that he realized I had gotten the pre-production unit by mistake; neither of us were aware of it prior. As it turns out there was indeed an air leak, something that had already been rectified in the production models. Phase Technology updated the review unit with new gaskets for the driver, PR and amp (using the same pieces that are on the full production units) then sent it back to me. I went through the entire battery of tests a second time -- movies, music, loud volumes, etc -- and never heard the air leak again, so the updates they made completely rectified the problem. Any WL-12 bought today will already have the new style gaskets, so this issue won't occur with those units.

Phase Technology recessed the driver and PR about .75" into their respective panels, which left a little of the MDF exposed. Instead of just leaving a raw edge though they painted it black, which I thought was a nice finishing touch. The WL-12 doesn't come with carpet spikes, just rubber feet, which realistically could benefit from being a little taller; I found when placed on carpet the WL-12 sunk in to the point where the driver could potentially make contact during heavy bass passages. I ended up putting the rubber feet onto small furniture discs, which lifted it up enough to allow sufficient room.

During my testing I did find that the grill could use some additional work. The frame is made from .5" of a plastic-like material, which proved to be less than rigid. The pins securing it to the cabinet don't do a very good job either, something that became apparent during my evaluation (more on that later). For a sub in this price range I think the grill should be a bit sturdier. The cloth material used is thin and acoustically transparent though, which is always a good thing.

The driver is an impressive unit. It consists of a mica-graphite cone with a thick NBR rubber surround. There's also a double stacked magnet with a sloping bump-out. The frame is cast aluminum and appears to be powder coated. It has venting for the voice coil, as well as vents along the base of the frame where it attaches to the magnet. All the vents are covered with a mesh grill too, so nothing can get in there. Pushing on the driver indicates the suspension is not all that rigid, yet during testing the cone really didn't move a tremendous amount.

The passive radiator is essentially the driver without a motor, impressive powder coated frame and all. It appears to be just as stout. Both the driver and PR are secured using T-nuts, which is always the best method in my opinion. The amp has a quality look and feel, topped off with a nice textured finish. The knobs and switches are solid and work with fluid, easy motions. Phase Technology says this is a "servo-controlled amplifier that monitors and adjusts output for dynamic, undistorted bass". According to Phase Technology this is how it works...

"Most filter circuits work in one of two ways. The first type accomplishes it's task by compressing the signal, which reduces the dynamic range at the output of the amplifier. For this type of filter the difference between the quiet and loud passages are greatly reduced. The second type operates just like a limiter; no matter how much the input increases the amplifier will only produce a set amount of power. This type of filter cuts off the dynamics once it reaches the limiter. The Phase Technology servo control is different; it constantly monitors the output of the amplifier to prevent the input signal from over driving the amplifier and/or woofer without reducing dynamic range. It does this by looking at the duration and level of the signal and allowing dynamics to be produced, and limits them only if they will produce audible distortion. The advantage of this is that the WL-12 produces the movie sound track or musical score with all the impact and dynamics that were originally recorded."

Hooking up the WL-12 really couldn't be any easier; plug in the power, connect an RCA cable from your receiver to the LFE input, set the gain and phase, then turn the Lo Pass dial to "LFE" (which bypasses the crossover entirely, and uses the one from your receiver instead). That's it. There are no line level, speaker level or XLR inputs, nor are there outputs of any type, so the amp is about as straightforward and unintimidating as you can get.

With the WL-12 there's one additional option to consider; wireless. The transmitter is very small, able to fit in the palm of your hand. Like the rest of the WL-12's hook ups this one is quick and simple. Just plug the transmitter into an RCA cable attached to your receivers subwoofer/LFE output, insert it's power cord and plug that into a wall socket. Then you hit the reset toggle switch on the back of the sub itself and finally depress the reset button on the bottom of the transmitter. The amp comes with it's own built-in wireless receiver, so it works right out of the box. Once the WL-12 synchronizes with the transmitter -- which took mere seconds -- you're done. The communication between the two devices is in an uncompressed format, so there's no loss of fidelity (versus wired) if you opt to go this route. According to the manual it's good for up to 50 feet.

So how does the wireless work? In a word, perfectly. I had no problem synchronizing the transmitter to the WL-12. I placed the sub in several different locations in my room and it worked flawlessly each time. I even tried placing the sub in a completely different room, to see if the transmitter worked through a wall. Sure enough, everything was fine (although it was a little bizarre to hear the bass coming from a hallway behind me!). For people who hate to run wires, or just want total placement flexibility, Phase Technology's wireless is an indispensable feature to have.

The connectors, dials and switches on the amp are all clearly marked and legible, making everything easy to configure and use. The only control I feel is missing would be Always On; with the WL-12 your power choices are Off or Auto On. In this case Always On might be a good feature to add because I found it didn't always come out of standby until the volume was on the high side. It also tended to go back into standby mode a little too quickly. There were times while watching something like a sporting event that the sub would shut itself off, only to come screaming back to life when a commercial came on.

My living room is 13x17x8 (1768 CF), so it's not terribly large. The main seating position is approximately 11 feet from the subwoofer. All testing was done after the unit had been broken in for at least 15 hours.

Looking at the physical size and driver complement of the WL-12 your initial expectations are probably going to be somewhat reserved. After all, not one single dimension is even a foot and a half, so it certainly isn't imposing. Thankfully the WL-12 is more capable then it's appearance would indicate. Using it on an everyday basis -- whether watching TV or movies -- you quickly come to realize that this is an accomplished little subwoofer. It makes almost all the right sounds at the correct time with the proper amount of emphasis. Rarely do I forget that I'm reviewing a subwoofer, but in this case I did a few times. The WL-12 blended so well as to become virtually seamless.

As you may expect, due to it's size, headroom is not this subwoofers strongest attribute - clarity, definition and mid-bass punch are more it's forte. Don't take that to mean it can't play loud, because it can, just that it doesn't appear that was the over-riding design goal for the WL-12. Bass was reproduced correctly and accurately, with both movie soundtracks and music. It seemed quick on it's feet too, rarely sounding as though it was falling behind. Only when the WL-12 was forced to play very loudly did the clarity begin to suffer, but that's expected of such a small subwoofer. For the most part it was well behaved and a pleasure to have in my HT system.

I run each test scene twice; once while seated in my normal listening position, and then a second time while sitting a few feet from the subwoofer. This allows me to hear it as I normally would, yet also affords me the opportunity to determine if it's straining even the slightest bit. Both tests are run at the same volume level.

Like most people I have specific movies and particular scenes I use when testing subwoofers, all of which I used here. Each individual test is listed below in the format of Movie: Scene.

Lord of the Rings: Bridge of Khazad Doom - There is an ultra low frequency rumble in portions of this scene, as well as significant amounts of impact generated by numerous structures crumbling. For a subwoofer to handle all of that properly it needs to be fast, precise and capable of reaching very deep, otherwise a lot of it comes across as nothing more than annoying resonance. This scene was delivered almost perfectly by the WL-12.

With the exception of the aforementioned low level rumble -- which could have been a bit deeper -- the Khazad Doom scene was rendered beautifully, with a tremendous amount of mid bass impact and even a bit of "feel" that reached my chair. The crumbling structures sounded exactly like what a crumbling structure should sound like. So smooth and crisp was the bass that I ended up replaying this scene a few times.

My favorite part of this scene to play around with is the Balrog's roar. There's an instance when you see it for the first time that I just love to crank way up. He jumps out of a cavern and lands right behind the Fellowship with a thud, and then lets out a fire-breathing roar. I enjoy seeing how loud I can play that part. The WL-12 did very well, and handled the ever increasing volume with relative ease. Even the huge impacts created when the Balrog's feet hit the ground as he chases after the Fellowship came through with a pretty solid impact. But then came "the sound"...

As mentioned previously, I played this scene a few times because I was rather impressed with the vast majority of it. By the 3rd or 4th time I began to hear a strange buzzing noise. At first I thought it might be the window blinds or perhaps a rattling closet door, but after poking and prodding various things I came to realize that's not what it was at all. Further exploring lead me to the true culprit; somewhere during this scene the grill had been dislodged by the bass, and two of the four pins were pushed out of their respective sockets on the cabinet. I popped them back in and started playing this scene again, but after a few more passes they did the same thing again. I decided it wasn't worth playing with any longer, so I simply left the grill off for the remainder of the review.

Collateral: Club Fever - Although this scene doesn't contain a tremendous amount of LFE information it does have a driving musical soundtrack and over-emphasized gun sounds. The music portion I've found can cause trouble for a subwoofer because it does tend to drown out the voice track in certain spots, especially if it lacks clarity and speed. Because of that articulation is crucial. The WL-12 played this about as well as any subwoofer I've heard recently.

The club music sounded like, well, club music; bass-heavy pounding, with questionable clarity. However, that's how the scene is recorded so the WL-12 did what it was supposed to do. Voices, which can sometimes be problematic in this scene for a subwoofer crossed over at 100Hz, were accurate and distinct. And the over-emphasized gun shots? Deep and powerful, without a hint of bloat or sloppiness. Not much more to say here; the WL-12 simply worked, and worked well.

Avatar: Assault on Home Tree - For those familiar with the movie this scene has low frequencies, ultra low frequencies, explosions, gunfire, voices and enough other things going on to provide a good subwoofer test. Unless you really pushed the volume nothing in Avatar seemed to faze the WL-12.

As the gunships approach Home Tree you can almost feel the underlying intensity. The roar of their engines, the sound of the rockets being launched, the impact of each explosion, the crackling of the massive roots as the tree begins to list, and all the way to the point where it's toppled and crashes into the ground the low frequency was pretty much spot on, with good clarity. There were actually a few instances where impacts created some tactile feel, which is pretty impressive for such a tiny subwoofer.

I tried several other scenes that have deep bass -- specifically Battle for Pandora, Fall of the Heros and Eywa -- and I wasn't disappointed by anything I heard. Perhaps my favorite part was the subtlety and definition each of the elements had; when the bass was supposed to be deep it was, when it was supposed to hang back a little it did. The WL-12 generally exhibits good overall dynamics and balance. I say "generally" because there were occasions where I think the transient response could have been a little better; sometimes the various bass elements would blend together and lose a bit of distinction during scenes where an intense battle was raging. This was the exception to the rule though, because the vast majority of the time the WL-12 kept it's composure and was able to handle whatever I threw at it.

War of the Worlds: The Machine Emerges - The archetype. Perhaps the most recognized subwoofer test scene of all time. The depth and volume of bass that occurs during a several minute span in this scene is simply amazing. If you want to see what your sub is capable of this scene can certainly be used as a barometer. With subterranean vibrations, exploding pavement and collapsing buildings you have ultra low, low and mid-bass frequencies pouring out of your subwoofer. One of the most punishing combinations there is, and an excellent way to really push something to the brink. Other then the limiter kicking in, and attenuating a bit of the subterranean bass, the WL-12 did very well with this difficult material.

When the alien first starts to move underground the low level rumble in the soundtrack can turn into a sloppy mess if a sub can't play deep and clear. The WL-12 missed the very lowest notes, but the effects were both solid and clear with the various sounds being distinct. As the ground buckles the WL-12 put out a strong and deep tone, with trenchant cracking sounds. All-in-all, this scene had good authority and definition for a subwoofer this small.

In The Storm was a nice treat as well, with clearly defined and precise bass elements. There was just the slightest bit of ultra low missing as the lightning struck the ground, but it was still a nice clean impact sound. Both the plane crash and subsequent explosion in At The Window were rendered wonderfully. The Heat Ray scene turned out to be the best of them though, which was produced with a precise, deep and convincing sound. In particular, the destruction of the house towards the end of the scene had an almost concussive effect.

10,000 BC: Mammoth Hunt - During this scene there's either ultra low bass or mid-bass, with very little in between it seems. The WL-12 came close to hitting the mark, but fell just a little shy.

Rarely did I find the WL-12 lacking precision or articulation -- quite the opposite, actually -- but every once in a while it seems to be missing just a touch of bottom end. Not weak, mind you, just not quite what a particular scene calls for, from a visceral perspective. For example, while the mammoths are simply milling about the sound of their feet hitting the ground has just about all the detail you could want, but the impact is a touch short of convincing. I would have liked to feel a little more. When the stampede occurs it's the same thing; the clarity is good, and you can almost hear each individual thud from the dozens of feet crashing into the ground, but the tangible vibration was a bit subdued. Certainly not anemic, but perhaps 90% of what's required to impart realism.

I did try a few other movie scenes I've been experimenting with, but had mixed results. Tron: Legacy had a nice solid punch with clear, deep bass. All the effects had the proper weight, with nothing out of balance. Underworld: Awakening proved not to be the WL-12's favorite movie. Scene 10, where Selene has a fight with that massive beast in the underground lair, caused a few complaints from the driver that were audible at my listening position. As the beast approaches the thudding emanated from his footsteps is some of the lowest bass I have every heard in a movie, so it's not entirely unexpected that this could upset a subwoofers balance. Scene 5 of Ironman, where Tony Stark escapes from his captors, was good for the most part as well. When he exits the cave there's a similar effect to Underworld: Awakening - massive thuds from his feet. Here again the WL-12 was a little unhappy, producing those footsteps in a somewhat less then clear manner (seems like the WL-12 doesn't like footsteps :)). Scene 4 of Master and Commander -- Under Attack -- was the opposite; the canon fire, impacts and explosions were full and rich, making this scene realistic and engrossing.

Adding additional test scenes to any evaluation is a good sign, because it means that I'm pretty happy with what I'm hearing. There were a few instances where the WL-12 struggled, but the vast majority of what it produces is strong and solid, with excellent definition and clarity. Even with the extra scenes the amp never got hot; it was on the high side of warm, but not uncomfortably so. During normal operation the amp maintained a very acceptable temperature level, being just barely warm.

I use a combination of lossy and lossless material (both MP3's and CD's) to see how musical a subwoofer is. The WL-12 has good clarity and warmth, but could benefit from a touch more "speed" to really take it to the next level.

I tested it with a variety of music -- from Pink Floyd to Johnny Lang to Motley Crue -- and found the sound to be very pleasant. Bass guitar and kick drum exhibited good accuracy, with solid definition. I also watched the DVD of Foo Fighters at Wembley Stadium, which has a very well recorded soundtrack, and felt the same way; the WL-12 produces enough articulation to make music enjoyable.

When I switched to electronic music the results were similar. There was sufficient detail to pick out the individual notes with relative ease, but the slight issue with extension became a bit more pronounced due to the fact that this music really pushes those boundaries. The Bass Mekanik CD Quad Maximus, as well as Bass-o-tronics Bass I Love You, didn't quite have that ground shaking sensation they're both famous for. Realistically though, the WL-12 is capable of producing as much low bass output as perhaps any other subwoofer this small.

One interesting thing I noted was that even with electronic music pounding away the driver and PR did not exhibit a tremendous amount of movement. I experienced this same phenomenon during the movie tests as well; even during very deep bass passages the driver and PR seemed to be under better control then other such systems I've reviewed.

Unfortunately I wasn't able to test Phase Technology's support. There's no way to send them just an email, you have to fill out a form on their website. That's not exactly the industry standard method, but it's not terribly uncommon either. What is non-standard, however, is the amount of information you have to provide before you can hit the Send button; name, address, city, state and zip (along with what you want to ask them, of course). Since I don't want the fact I'm doing a review to influence the quality of support received I try to remain incognito. Supplying all that information would have compromised anonymity, so I opted to forgo testing support.

However, I was in contact with Ken Hecht directly on several occasions during the time I had the WL-12 and always found him to be a pleasant person to work with. One has to assume that if the president of the company conducts himself professionally the rest of the employees will follow suit.

Overall the Phase Technology WL-12 proved to be a well rounded, solid performing subwoofer, especially considering how tiny it is. The curved cabinet and nice veneer finish project a unique appearance, separating it from a sea of generic black box subwoofers. The driver and PR are both high quality pieces, as is the amp. Add to that the fact it's a 100% domestic product with a very long warranty period, backed by a company who's been in business for over half a century, and you have quite a package. The grill could benefit from an updated mounting system -- and having a little more lower extension would be a bonus as well -- but the WL-12 is a well executed unit with perhaps only one meaningful drawback; it's price. At $1560 it's expensive, even for a wireless, servo-controlled subwoofer. I did find the WL-12 selling on the internet for around $1000, but I'm not sure if that was from an authorized source so that may not be an option. Regardless, if you need a truly diminutive subwoofer, and have the cash, the WL-12 is definitely worth your consideration.

Please use the Phase Technology WL-12 Review Discussion Thread for Questions and Comments

Frequency response. Blue is the driver, green is the passive radiator.

The measurements were taken using XTZ Room Analyzer II Pro. It was close mic with the tip of the microphone pointed directly at the center of the driver and PR, and on the same plane as the leading edge of the surround. The sub was indoors, physically positioned in the center of my listening room. No other speakers were running.
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