Monoprice Monolith 12” and 15” THX Ultra Subwoofers
Exploring new depths.
REPRODUCING A MOVIE soundtrack in a home environment isn’t an easy task. At your local cinema, the theater will hopefully have sound dampening so you don’t hear outside noise. And if you’re lucky, the system will be calibrated properly and provide enough headroom so there’s no clipping or distortion during the dynamic portions of the soundtrack.
In most homes, you have to contend with a lot of extraneous factors. The acoustics may not be right, with the room being too bright (not just sound-wise but also light-wise) or too dead (making for lifeless audio). This can affect your enjoyment of the movie. Furthermore, the quality of your gear matters. Sure, a 32-inch budget TV and soundbar from the local big-box retailer may be fine for watching the news, but do you get the visceral impact that’s required when Luke blows up the Death Star?
While every component plays its part in the presentation, the subwoofer is arguably the one that can make the most noticeable improvement to a budget home theater system. When I have visitors over, they often marvel at the size of the screen (though, at 88 inches diagonal, it’s still pretty modest by serious home theater standards). If I pop in a Dolby Atmos demo, they’re amazed by the sound coming at them from every direction. But I get the biggest reaction, by far, when a bottom-heavy scene comes up: “I can’t believe how much I felt the bass,” they’ll usually say. “The entire floor was vibrating!”
Editor-in-chief Rob Sabin calls me the resident basshead at Sound & Vision, and that’s a badge I wear with honor. My reference system includes four subwoofers: an SVS Pc-ultra, a Hsu Research VTF-15H MK2, and dual JL Audio Fathom f110 cabinets, all calibrated using the freeware program REW and a minidsp to get the subs to play nice with each other. It took me days of calibrating to get the quartet just right, but if you care about bass like I do, it’s time well spent.
New Kid on the Block
Being the basshead of S&V gives me certain perks—among them, the opportunity to sample a lot of subwoofers and be one of the first to do so. Enter Monoprice, best known for cables that deliver high-quality picture and sound at prices the masses can afford. As time has gone on, the California-based company has started to expand into self-branded components—such as Monolith amplifiers, one of which I reviewed quite favorably in our
June 2016 issue (also available at soundandvision.com), and now Monolith Thx-certified subwoofers.
These new subs come in three different sizes: the 10” THX Select and the 12” and 15” THX Ultra. The latter two are the subject of this review. The conception of THX goes all the way back to 1982 and was the brainchild of George Lucas, who was not pleased with the way theaters were showing his films. He hired audio scientist Tomlinson Holman, who set up a rigorous program that started at the production studio before reaching theaters and, eventually, home components. THX certification comes in four flavors: Compact, Select, Ultra, and Dominus. THX Select applies to rooms up to 2,000 cubic feet, and THX Ultra is for rooms up to 3,000 cubic feet. To attain Ultra certification, subwoofers (and other speakers) must undergo myriad tests—for
sensitivity, frequency response, distortion, etc.—and be able to play at 85 decibels and have +20 db of headroom at the specified listening distance. The takeaway is that THX Ultra subs must have low distortion and the ability to play down to at least 20 hertz.
The internet-direct subwoofer market is extremely crowded, especially in the realm below $1,500. The Monolith 15” sub checks in at $1,300, with the 12” version at a relatively budget-friendly $800. Currently, shipping is included with these prices, which makes them very competitive.
The ported designs give both models substantial SPL capabilities.
Specs-wise, both subs check all the right boxes. The 12” has two ports and sports a 500-watt Class D amplifier built around a Texas Instruments 48-bit data path (with 28-bit filter coefficients) and DSP engine. The 15” has three ports and is powered by a 1,000-watt Class D amp built around the same Texas Instruments DSP engine. The use of ported designs allows both models to have substantial SPL capabilities, and port plugs let you customize the character and extension to fit your particular room and tastes.
Not Your Typical Black Box
Generally speaking, subwoofers won’t be entered to win any beauty contests, but these Monolith subs
are quite attractive. For each, Monoprice has chosen to use chamfered corners that provide an octagonal shape to the front face versus a boring square box. The woofer, embossed with a Monolith logo, can be covered using the removable grille, which is floated slightly away from the baffle. The cabinet itself is built with HDF (high-density fiberboard), which adds to the weight significantly, but this does help the sub maintain a sonically inert structure.
Each driver has been customized for Monoprice and appears to be well constructed to provide extreme cone movement. The 12inch woofer is specified to be capable of more than 80mm peak-to-peak mechanical excursion; the 15-inch woofer expands this to more than 90mm. To put that in perspective for the U.S. audience, that’s 3.15 and 3.54 inches of front to back cone movement, respectively.
Connections on the back panel include stereo line level inputs, an XLR balanced input, an XLR passthrough, and an IEC power cord socket. There are six controls on the amplifier: three knobs for Crossover, Phase, and Level and three toggle switches for Crossover (On/ Off THX), EQ (Extended/ THX), and Power (Auto/ Always On). Unfortunately, Monoprice doesn’t provide a PEQ (parametric equalizer) or control via a smartphone app, as can be found on some subs from competitors. I consider a PEQ and app control as nice-to-haves, not have- to-haves.
As I stated earlier, the Monolith subwoofers check all the right boxes. But how do they sound? Spoiler alert: awesome!
Not for Girly Men
Unboxing either subwoofer is a two-person job: The 12” weighs just under 100 pounds (98.5, to be exact), and the 15” weighs 128.5 pounds. Then there’s the added weight of the double-boxed shipping container. There are no instructions for unpacking the beast, but it’s best to open the top of the outer box, slowly flip the whole thing over, and lift the outer box off the inner one. Repeat the process to remove the sub from the inner enclosure; your back will thank you. Each sub has spiked rubber feet, so it’s best to use some sliding furniture movers (available at your local hardware store) to position it. Monoprice includes a pair of white gloves in case you want to provide your own white-glove service and keep oily fingerprints off the satinfinish, black ash vinyl.
Given their size, neither of the subs would fit in the preferred front left corner of my room, due to a fireplace hearth and my wallmounted front left speaker. (I usually put the small-footprint, cylindrical SVS Ultra there.) So I placed each of the Monoliths in Position No. 2, which is along the right side of my room, about a third of the way— where I usually keep my reference Hsu Research sub.
I set up two user profiles—one for the 12” and the other for the 15”—in my Anthem AVM 60 pre/pro and calibrated the speaker output levels using an SPL meter and test tones from a THX calibration disc.
As mentioned, you can choose to use either sub sealed by installing the provided port plugs. This will give you the tightest bass, at the expense of some low-frequency extension. Or, given the multi-port design, you can close one of the two ports on the 12” or two of the three ports on the 15”; by doing so, you’ll get the greatest extension at the expense of reducing maximum output. I listened to both subs in this extended mode, as well as with all ports open. For music, I really liked all ports open, but for movies, I preferred the extended mode.
My go-to audio tracks to test subwoofers include Justin Bieber’s “Baby,” Regina Spektor’s “Fidelity,” and Joss Stone’s “Sleep Like a Child.” I moved back and forth between the 12” and the 15” with each of these songs multiple times, and I was surprised at how well the 12” was able to hang with its larger sibling. In a lot of cases, the 12” was a tad tauter, but I’m really splitting hairs between the two subs when it comes to music: Both sound fantastic.
On some bass-intensive rap tracks, such as N.W.A.’S “Dope Man,” the 15” definitely showed that it could dig a little deeper and play louder than the 12”, which foretold what I would hear later with movie soundtracks. Of course, that shouldn’t be a surprise given the 15” sub’s larger enclosure, woofer, and amplifier.
The Ultra HD Blu-ray of Pacific
Rim is one of my favorite discs in the new format. Not only does it boast fabulous-looking HDR, but the Dolby Atmos mix is a stellar example of the breed with its ample use of overhead effects and its deep, sub-20-hz bass content. In the movie, after the Jaeger battles the Kaiju off the coast of Alaska, the Jaeger makes its way to shore while a grandfather and his grandson search for treasure with a metal detector. With the 15”, I could literally feel the approaching giant before I saw him come through the fog thanks to its reproduction of the accompanying low-bass information. The same scene on the 12” didn’t have quite the same visceral impact. Granted, my room approaches 5,000 cubic feet, so it really puts the 12” in a situation beyond its intended application.
In most every case, I was able to hear—and feel—either subwoofer deliver movie sound that had ample bass above 20 Hz, such as the dive-bomb scene on the beach in the first part of Dunkirk or the battle in “Blackwater” (season 2, episode 9) from Game of Thrones. Each sub was able to cleanly reproduce articulate bass with good extension down low and plenty of output, although I always got more oomph with the larger sub.
To be fair to the 12” and gauge its performance in a more suitable space, I spent some time with it in my secondary system that’s housed a 1,100-cubic-foot room. In that room it performed marvelously with movies. So this certainly is a case of choosing the proper subwoofer, or quantity of subwoofers, for the environment. I’m sure that dual 12” Monoliths would have performed flawlessly in my larger theater.
Double the Fun
Monoprice has definitely impressed me with their initial offering of Thx-certified subwoofers. Each warrants a Top Pick—but if you can swing the extra cash for the 15” model, it would be my preference, especially if you have a large room. One thing worth repeating: In order to receive THX certification, these subs need to meet a low distortion number, which really translates to clean and controlled bass response. I truly enjoyed my time with both of these subs and wouldn’t hesitate to recommend them to a friend, but I would add to this my usual adage: Two is better than one, because, well... there’s never such a thing as too much bass!
I could literally feel the approaching giant before I saw him come through the fog.