When I was recently asked to review the flagship M&K Sound S300 Series monitors, M&K Sound also sent along their X12 subwoofer to round out the 5.1 speaker system. While this review focuses on the THX Ultra 2-certified X12 subwoofer ($3,200), my impressions are within the context of the X12 sub as an integral part of that 5.1 system. If you missed the review of the impressive S300 Series monitors, you can check it out here.

As I was preparing to write this review, the lyrics of the current pop song by Meghan Trainor kept running through my head. Because when it comes to subwoofers, it really is "all about that bass, 'bout that bass, no treble." While subs are about the bass, for me the real magic happens when a sub can produce taut, punchy bass and also blend seamlessly with the other loudspeakers in the system. I don't like it when a sub draws attention to itself. You know, subs that scream, "Look at me, I'm right over here!" I like subs to disappear by providing a solid foundation that simply extends the sound spectrum.

The high-end X12 subwoofer uses two identical 12-inch drivers mounted in opposite phase in a push-pull arrangement. The idea is that the distortion generated by the in-phase and out-of-phase drivers cancels itself, resulting in significantly reduced harmonic distortion. Certainly in my extended listening experience, I couldn't dispute that claim. The X12 consists of a solidly built, internally braced, and sealed enclosure made with 22-millimeter-thick MDF panels. It is large, with dimensions of 17.3 inches by 26 inches by 18.1 inches, and weighs just shy of 80 pounds. Physics dictates that you need a large volume to generate deep, accurate bass without resorting to the use of ports. The Class D digital amplifier serves up 400 watts continuous and up to 700 watts peak power.

All connections and adjustment controls are located on the back panel. I'd rather see adjustments located on the front for easier access. M&K Sound thoughtfully offers the choice of both single-ended and balanced connections for inputs and outputs. Variable EQ, phase, and crossover adjustments are available. The X12 offers many connection options, including throughput options for assembling a complete THX setup and the input/output flexibility to connect to M&K Sound active monitors if you so choose. There is no onboard room correction software because M&K Sound claims that, by virtue of its design, the X12 interacts well with any listening environment with the right placement and adjustment.

Indeed, I found the X12 to be easy to dial in for optimal performance utilizing the Audyssey MultEQ XT32 software built into my Marantz AV8801 pre/pro. After doing some casual listening for a brief period of time, I reached for some dynamic classical music for a real test of the X12's capabilities. The lowest notes on a pipe organ piece I selected were about 20 Hz, and the X12 portrayed the music with authority without sounding like it was straining at all. When I played the rock band Imagine Dragons' track "Radioactive," there was a rumble like I've not heard before: more weight, more impact, more force to the music. The same held true when watching action-adventure films like Casino Royale (MGM Columbia) and The Dark Knight Rises (Warner Brothers) on Blu-ray.

The X12 offers a real sense of the "physical," allowing you to feel what great bass reproduction sounds like. I also found myself watching one concert Blu-ray after another as though I was hearing each one for the first time. The sub never got in the way of delicate passages but always brought appropriate bass authority to dynamic passages. Never muddy or thick, the X12 was just right. With the complete M&K combo, I frequently found myself losing track of time, I was having so much fun.

High Points
• The M&K Sound X12 sub's unique push-pull dual driver design and large cabinet volume enable it to play both really loudly and to the lowest limits of the audible frequency range with imperceptible distortion.
• The X12 sub blended so seamlessly with the S300 monitors that the source of bass was completely undetectable--which is the biggest compliment I can pay to this top-tier sub.
• Given the X12's effortless nature, sealed enclosure, and numerous adjustment options, it should blend well with a wide variety of loudspeaker makes and models.

Low Points
• The available controls are all located on the back of the X12 sub. This can make it challenging to make adjustments, especially when the sub is placed in a corner or against a side wall, which are common placement locations.
• Given the X12's size, you are not going to be able to hide this beast, and this no-nonsense top performer is only available in one finish: smooth black. Unless you have a dedicated media room, it may not blend well with the décor of a multipurpose living space.

Comparison and Competition
At the price point of the X12 sub, M&K Sound means to compete with the other big names in subwoofer design, and compete it does. If you're shopping for a new subwoofer in this range, you'll likely want to compare it against other upper-echelon 12-inch driver models, such as those from REL Acoustics, JL Audio, Paradigm, SVS, and Velodyne Acoustics.

The only subs I had on hand to compare with the X12 were my reference pair of JL Audio F110 subs. Given the single 10-inch drivers of the JL Audio subs, I decided to use both for my comparison against the single X12. Well, the M&K Sound X12 sub provided more volume at its reference setting than the F110 stereo subs while also playing lower into the audible region with accuracy. The X12 also performed its disappearing act with ease. What I learned is that, given the right sub, one is all it takes to enjoy a seamless and physical sound experience. Only if you have the largest of listening spaces would you need two of these subs.

You can check out more subwoofer reviews by visiting our category page on the subject.

Conclusion
The M&K Sound X12 subwoofer earns its place among the upper echelon of sealed subwoofers on the market today, with performance that equals or beats other well-known and respected competitors in its price range. If you're considering a sub at this level, you definitely owe it to yourself to arrange an audition. This is especially true if you're fortunate enough to have space for a dedicated media room. Given its ease of placement and its ability to help you feel what real bass impact sounds like, you won't be disappointed.

Additional Resources
• M&K Sound S300 Series Bookshelf Speakers Reviewed at HomeTheaterReview.com.
• Visit the M&K Sound brand page at HomeTheaterReview.com.