Over the past year or so, I've gained a newfound respect for subwoofers. It's not that I feel as if I undervalued them in the past; I've just come to understand them better as I've focused more on items such as setup and parametric EQ rather than driver complement and amplifier power. The truth is that both a sub's driver complement and amplifier matter little if your understanding of acoustics (i.e., placement) and EQ aren't there. As with anything, simply focusing on a product's spec sheet is possibly a great way to impress your friends, but it's also a good way to go broke in the process. It's only when everything is working in harmony that spec sheets "come alive." As with anything in life, but especially in regards to AV, the more effort you're willing to put into something, the greater the reward. This is doubly true for subwoofers. Half-ass your subwoofer setup, and you'll wonder where your entire system's performance has gone. Go the extra mile, and you'll swear you've upgraded every component you own - yes, the difference can be that dramatic. You might discover, as I did, how a subwoofer like the SX-1212P/R can quickly become the most important speaker in your system.
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The RBH SX-1212P/R (kind of a silly name) is the flagship subwoofer for the manufacturer's Signature SX Series of loudspeakers. It comes in a variety of different configurations, from non-powered to powered. In its non-powered configuration, the SX-1212 starts at a little over $2,000, and the fully loaded SX-1212P/R reviewed here retails for $5,300. While $5,300 may sound like a lot, compared with the subwoofers it squares off against - for instance, JL Audio's Fathom f212 ($6,200) and Gotham ($12,000) - it can be viewed as a relative bargain. While value is in the eye of the beholder, what I wanted to find out was if the SX-1212P/R was any good.
The SX-1212P/R is a beast of a subwoofer, arguably the largest I've encountered in my travels, at nearly 18 inches wide by 39 inches tall and 22 inches deep. It isn't light either, tipping the scales at a whopping 130 pounds. The cabinet, although large, is rather elegant in its design, featuring rounded edges that, when viewed from overhead, give the sub a somewhat oval shape. The standard finish is a sort of matte black; however, as with all RBH products, custom finishes are available for an extra charge. The SX-1212P/R's height includes pre-installed chrome legs or feet; further stability can be achieved by screwing the included spikes into the bottom of said feet. If you have hardwood or tile floors, you may wish to simply go with the attached feet au naturel. There is also the option of rubber tips that can be screwed into the bottom of the attached feet, which may also work for those with hardwood or tile floors. The front face of the SX-1212P/R features two large twelve-inch aluminum woofers, which are silver in color, an RBH trademark. The standard grille that covers the two woofers does a good job of shrouding their color, but it does not completely eliminate their visibility.
Around back, you'll find a large, elongated plate amp that is mostly heat sink with but a few input and control options. Working top to bottom, the first option you'll find on the SX-1212P/R's plate amp is its volume or level control. Below that is its input, which is balanced only, and its output, also balanced. To the left of the XLR input/output options, there are two small buttons: the top mutes the amp, while the bottom selects one of the two pre-loaded DSP programs. With the button pressed in, a low-pass filter at 80Hz will be enabled. When the button is left out, the low-pass filter will be defeated. There is a PS/2 port below the XLR input/outputs that allows the SX-1212P/R to be connected to a computer, presumably for integration purposes. Along the bottom you'll find a Neutric-style input (very pro of RBH) for the SX-1212P/R's included power cord, as well as an additional Neutric-style power output. Throw in a master on/off switch, and you've got the SX-1212P/R's plate amp all sewn up. What you won't find are controls for items such as phase and crossover, as those duties are designed to be handled by your AV preamp or receiver, at least as far as the SX-1212P/R is concerned.
In terms of its specifications, the SX-1212P/R has a reported frequency response of 17 Hz to 180 Hz, thanks in part to its 2,400-watt internal amplifier driving the two twelve-inch aluminum cone woofers. Since crossover and such are handled outboard via your AV preamp or receiver, the SX-1212P/R is dependent upon the other hardware's performance rather than its own in those regards.
Installing the SX-1212P/R (or should I say un-boxing and moving the SX-1212P/R) is a job for at least two people, maybe even three. I managed to un-box the monstrous subwoofer myself by opening the bottom of the box, then gently flipping it over and letting the SX-1212P/R slide out. However, muscling it upstairs to my reference theater was definitely a two-person job, which my wife helped me with, albeit begrudgingly. Once upstairs, I was able to walk the SX-1212P/R into its final resting place, which is approximately seven feet off my front wall and along my left side wall. In this location, the SX-1212P/R was approximately a third of the way into my room and approximately six feet from the center of my primary listening position. For the record, this is where most subwoofers that I review go, as I've found it to yield the smoothest response from about 35 Hz on up to 120 Hz - provided the subwoofer in question is up to snuff, that is. From about 25 Hz to 35 Hz, I have a noticeable dip of about six or seven dB, which is due largely to the nature of my room and its configuration, and is something that I combat with EQ. From 15 Hz to 25 Hz, things tend to be more linear.
With the sub in place, I went ahead and connected it to my nearby power receptacle, as well as my Behringer Feedback Destroyer Pro (BFD) via a 15-foot XLR cable from Monoprice. The BFD sits in my rack above an Integra DHC 80.2 in the adjacent room. I use the BFD as a parametric EQ for my subwoofers, while relying on the Integra for adjustments like distance, level and crossover point. To this end, the SX-1212P/R's simplistic plate amplifier served me well, as I typically bypass any and all controls that are usually found on most subwoofers in favor of those afforded me by my Integra or BFD.
The first step of any subwoofer review, for me, is to measure its response in my room. I do this by connecting my laptop to a Behringer UCA-222, which is a USB interface with both input and output capabilities. The UCA-222, when used in conjunction with my RadioShack SPL meter and the free program Room EQ Wizard, allows me to send test tones to the sub in question to measure its in-room response. With the SX-1212P/R's plate amp set to zero, the resulting volume of the Room EQ Wizard's test tone was a whopping 105 dB. Typically, with a subwoofer's volume set to "Reference," the out-of-the-box output will register somewhere in the neighborhood of 72 to 85 dB, not 105. With no other way to dial back the SX-1212P/R's output, I had to make some adjustments within Room EQ Wizard itself, as 105 dB is just too loud when having to take multiple measurements. Once I got the SX-1212P/R's volume to around 90 dB, I measured a full 15- to 120-Hz sweep. In my room, the SX-1212P/R managed 18 Hz on up through to 120 Hz with no problems. Between 25 and 35 Hz, the dip I referred to earlier was present; however, from about 35 Hz on up to 120 Hz, the SX-1212P/R's response tracked very linear. What do I mean by linear? No peaks or dips were greater than three dB, with the largest peak being somewhere in the vicinity of 2.3 dB. Even from 15 Hz to 25 Hz, the response tracked true. Impressive, to say the least. I expected low-end grunt, but not quite the level of top-end refinement that I got.
With initial measurements out of the way, it was time for Room EQ Wizard to create some filters in order to match my target curve. To minimize the naturally occurring dip in my room's response, I adjusted my target curve accordingly, thus reducing it to a dip of three or four dB, instead of six or seven. With the rest of the frequency response adjusted accordingly, Room EQ Wizard created a series of five filters that I dumped into my BFD. I then re-measured the SX-1212P/R's frequency response in my room. The results were not only more linear, but decay times had also improved dramatically. In truth, post EQ, I haven't gotten a sub to look this good on paper ... ever.
With the SX-1212P/R's EQ procedure out of the way, it was time to integrate it with my other speakers via my Integra DHC 80.2. First I set the crossover point, which for this review was 80 Hz, since the EMP Tek E5Bi bookshelf speakers were what I had on hand. Next I set distance, which as I stated before fell around six feet, give or take a few inches. Lastly, I level-matched the SX-1212P/R inside the Integra to match the other speakers. Keep in mind I still had the SX-1212P/R onboard volume set to zero. With the onboard volume at zero, I still had to turn down the SX-1212P/R's volume inside the Integra an additional 10 dB in order for it to measure 75 dB in my room and thus seat nicely with the EMP Tek speakers. Obviously, the SX-1212P/R is designed to move a lot of air in large rooms, but that isn't to say it can't also be enjoyed in smaller rooms. Minus the filters created in Room EQ Wizard, no other form of equalization (automatic or otherwise) was employed on the SX-1212P/R or any other portion of my system for this review.
Read about the performance of the RBH SX-1212P/R subwoofer on Page 2.