December 2009 Reviewed by Aron Garrecht	JL Audio Fathom f112 Subwoofer

Description Model: Fathom f112 Price: $2800 USD in satin black (add $100 for high-gloss black) Dimensions: 18.5"H x 15"W x 17.625"D Weight: 115 pounds Warranty: Three years parts and labor	Features Power modes: Off, On, Automatic signal-sensing 1500W (short term) class-D amplifier (manufacturer rated) Rated frequency response: 21-119Hz, ±1.5dB Crossover: 12dB or 24dB/octave Low-pass filter: continuously variable from 30 to 130Hz Polarity: 0/180 degrees Phase: continuously variable from 0 to 280 degrees ELF Trim: -12dB to +3dB at 25Hz 12" driver Sealed enclosure

JL Audio has long been one my favorite manufacturers -- not for their reputation for great bass or the attractive appearance of their products, but because they continuously produce exceedingly well-engineered, high-quality components. The resulting performance is a byproduct of that engineering-driven philosophy, and in my experience, that performance is nothing short of exceptional. So when asked to review JLA’s Fathom f112 subwoofer, my reply was a resounding Yes. With its 12" cone, 1500W class-D amplifier, and price of $2800 in satin black (add $100 for high-gloss black), the Fathom f112 is positioned directly above JLA’s 10", 1000W Fathom f110, and below their 13.5", 2500W Fathom f113.

Inside its thick cardboard box, the Fathom f112 sat on four balloon-like feet designed to absorb any heavy impacts during shipping. Removed from its packaging -- or, rather, once the packaging had been removed from the f112 -- the subwoofer sat upright, ready to be positioned, hopefully with the help of a friend: this little beast weighs 115 pounds. Kindly included was a leather-like case containing a pair of white cotton gloves for keeping the gorgeous finish free of scratches and fingerprints, a microphone with lengthy cord for JLA’s Automatic Room Optimization (ARO) system, and a heavy, grounded power cable. My sample, finished in high-gloss black, looked, in a word, classy.

It was immediately apparent that the Fathom f112 is an intelligently engineered subwoofer packed with quality and technology. I was delighted to discover that all adjustments can be made from a panel concealed behind the sturdy front grille, rather than on the rear. Hats off to JLA for making such a simple yet effective ergonomic change, which helps eliminate the tediousness of setting up a typical subwoofer. On this attractive, aluminum-trimmed panel are switches for Power, Light, Input Mode, Level Mode, Polarity, and ARO Defeat. Knobs are provided for LP (low-pass) Frequency (30-130Hz), Extreme Low Frequency (ELF) trim (-12dB to +3dB at 25Hz), Master Level, and Phase. Curiously, there is no high-pass filter. Around back are pairs of input jacks: Neutrik XLR (balanced) and Cardas RCA (unbalanced). There’s also a single XLR output for running a second, slaved sub.

Technology

Below the control panel is the heart of the Fathom f112: its 12" drive-unit. The design of this overbuilt assembly yielded no fewer than six patents and has resulted in a superb-sounding driver capable of over 3" of travel, and reproducing frequencies from 119Hz down to an incredible 19Hz, -3dB. Those 3" of excursion are largely due to JLA’s Dynamic Motor Analysis (DMA), a proprietary system designed to control a driver’s motor system so that its performance remains linear over an extreme excursion range. Furthermore, a special surround was developed that spans the driver’s mounting flange and thus takes advantage of the entire driver diameter. The new surround permits the use of a wider roll, which is needed to control the cone’s high excursions without sacrificing any of the cone area.

Several other patented technologies were used in this motor design, such as in the cone assembly, which JLA calls W-Cone. This construction is said to result in astounding stiffness with minimal mass. Even the shape of the cone is optimized to provide improved torsional rigidity. JLA extensively researched and tested how the basket interacts with and affects the performance of the drive-unit as a whole, and incorporated slots directly above the top plate that deliver cool air directly to the speaker’s voice coil. To further lower the operating temperature, they cross-drilled the pole-piece, which assists in directing air to the voice-coil former, thus increasing power-handling capacity and heat dissipation.

The f112 is powered by a 1500W class-D switching amplifier that has a large toroidal transformer, and circuitry designed to exude tightly controlled, articulate, yet powerful bass.

Optimizing all this technology to perform at its best in your room is JLA’s Automatic Room Optimization system. In a nutshell, ARO directs the subwoofer to emit a series of tones that are picked up by the supplied microphone, which has been placed at your primary listening position. These readings are then analyzed by the ARO software installed in the f112. ARO then applies to the analyzed data a filter to correct or smooth out a single frequency-response peak.

Setup

Once I’d placed the Fathom f112 in my room and hooked it up to my system via a single unbalanced subwoofer cable from River Cable, I made sure that the subwoofer crossover in my Rotel RSX-1058 A/V receiver (which I use only as a preamplifier-processor) was set to 80Hz, and was ready to begin the ARO process. However, I noticed a slight feedback hum emanating from the f112. Luckily, JL Audio provides a possible cure for this problem, which often occurs when, as in my system, a number of other components are plugged into the same circuit: running the f112 in its Grounded or Isolated configuration. I switched to Isolated mode (recommended) and the f112 fell silent. Now I was ready to run the ARO software.

Running ARO couldn’t have been easier. All I had to do was connect the microphone, position it at the usual level of my ears when I sit down, then press Calibrate on the f112’s front panel. Typically, the ARO process takes about three minutes to complete, but in my case it took a bit longer -- the first few tests indicated that the subwoofer level was too low at my listening position. This was no surprise; at the seating position I prefer in my cavernous room, there’s always been a notable drop in response from about 25 to 40Hz. I adjusted the f112’s Master Level control to 3 o’clock, the ARO completed its task, and I was on my way.

Performance

Properly setting up a subwoofer(s) can be tricky. There are several variables to consider: room volume, the placement and number of subwoofers, crossover points, interference with other components -- the list goes on. This can prove daunting for some, especially those who prefer the plug’n’play approach.

But after I’d run ARO, I was beside myself at how full and well-balanced the bass response now was in my room, and how easy it had been to achieve this level of performance. Music through my B&W 804S speakers had an entirely new level of body and bottom-end authority, yet the Fathom f112 never drew attention to itself. After hearing the changes the JLA installation had wrought in my system’s two-channel sound, I was eager to hear if it would maintain that level of performance with 5.1-channel surround.

My first stab at punishing the Fathom f112 was chapter 9 of Michael Bay’s Transformers, in which a steel scorpion attacks a military squadron. Gunshots from the air strike were articulated very quickly, with effectual punch, yet without the boomy smearing that can sometimes occur in the reproduction of fast, successive bursts of low bass. The sub’s integration with the output of my B&W CCM 816 rear surround speakers was flawless -- multiple explosions in the rear soundstage had tight, deep impact, and were perfectly placed. The same held true for full-impact, front-and-center explosions -- the f112 made my B&W HTM4S center-channel speaker sound twice its size, and added to Transformers a level of realism I hadn’t previously experienced. And in the slow-motion segment in chapter 20 the f112 trumped itself, grunting out an incredible amount extreme subbass while showing no sign of strain or cabinet colorations, both of which are common at such high output levels. By contrast, my previous subwoofer, a B&W ASW 750, would sometimes bottom out in this scene, and its cabinet resonances were often audible.

Thoroughly impressed by the Fathom f112’s performance with Transformers, I raised the bar from mere punishment to outright torture: chapter 14 of Jonathan Mostow’s U-571. In one scene here, a U-boat manned by American sailors is being depth-charged by a German gunship. Fast-paced underwater explosions take place with varying degrees of impact and decay, and the f112 never missed a beat. In fact, the f112’s authority in its reproduction of the varying levels of attack and decay of these explosions, and their placements in the soundstage, resulted in a new level of three-dimensionality for this scene. Each explosion, whether subtle or tooth-rattling, was reproduced with tremendous punch and authority, but still articulately enough to be easily differentiated from the soundtrack’s other deep-bass effects. At this point, trying to find fault with the Fathom f112 began to shift from an exploration of its limits to a personal challenge.

Which is why I next played Jan de Bont’s The Haunting. If the other two films are punishing and torturous for most subwoofers, this one is borderline murder. I found the performance of the f112 in this film to be, in a word, seductive. The frequent background rumbling from the house was deep and smooth, giving the film a new level of tension. Where most subwoofers fall apart is in chapter 17, when the house comes fully alive; the extreme-low-frequency demands are not only intense, but outright loud. During this scene’s peak moments with my old ASW 750, despite its output being sufficiently forceful overall, I could constantly hear the driver straining and the cabinet creaking. The Fathom f112 delivered deep, thunderous bass with impressive grunt. I could not only hear but literally feel the bass in the room. That said, I did finally notice the f112 drawing a bit of attention to itself by exhibiting the slightest bit of strain as it met the limits of its piston’s excursion. Remember, though, that I’d had to increase the Master Level to 3 o’clock to compensate for that 25-40Hz dropoff. In a room of normal size, I expect that the f112 would continue to perform flawlessly with the Master Level set to about 12 o’clock.

Comparison

When I bought my B&W ASW 750, it had just appeared on the market and seemed a bit of a bargain, considering it was then one of the few subs that had a 1000W class-D amplifier, a 12" paper-and-Kevlar cone, a classy-looking ported cabinet veneered in real wood, and a frequency response rated all the way down to 16Hz, -6dB (which is actually lower than the f112’s rated output of 17Hz, -10dB). For the past five years, I’ve been quite pleased with it.

Well, times and subwoofer technology have changed. In my time with the Fathom f112, one thought kept occurring to me: Why hadn’t I done this sooner? I hadn’t expected this much improvement over my ASW 750. One of the things that the B&W has that the JLA lacks is a high-pass filter, which can come in handy when listening to two-channel music. But that’s the Fathom’s only lack. JLA’s ARO software absolutely trumps the now-antiquated system the ASW 750 uses. B&W’s approach includes a switch that offers two options: A provides maximum bass extension, whereas B gives up some of the bottom end in favor of maximum output.

The differences between the subs were never clearer than when I watched The Haunting. The B&W definitely delivered the dynamic punch, but the JLA, in addition to eliminating all of the B&W’s cabinet noise and chuffing, was much better at articulating low-frequency details. For example, in chapter 17, the JLA gave me a gut feel for where the low-frequency emanations were coming from onscreen: the ones from behind the walls weren’t quite as deep but were much faster than those coming from the floors and ceilings, which had the greatest impact and lasted longer. All of these sounds were better delineated through the JLA, indicating a higher level of bass control. This was especially true at higher volumes.

Watching Gore Verbinski’s Pirates of the Caribbean movies revealed another clear difference. Something I’d never heard through the ASW 750 was the low-level detail associated with the creaking of the ships’ wooden hulls. Now these sounds took on a whole new texture, making it feel more as if I were on the ship itself, watching the movie being performed as a play in front of me. This no doubt was also due to how well the output of the f112 integrated with that of not only my B&W 804S main speakers, but the rest of the speakers as well.

Conclusion

JL Audio’s Fathom f112 continued to impress me throughout the review period. From its seamless integration with the rest of my speakers to its powerful and accurate delivery of subbass material, it vastly improved the soundstaging and realism of my home-theater system. My only qualms about it were very minor: It would be nice to have a high-pass filter when listening to two-channel material, and a remote control would perfect its ergonomic design. The only other improvement I can think of would be to have two f112s.

Until that happens, the single Fathom f112 I have has become my reference subwoofer. If you’re in the market for a wonderfully versatile subwoofer that offers deep, controlled, powerful bass, looks classy, and is impeccably built, JL Audio’s Fathom f112 deserves to be on your short list.

Manufacturer contact information:

JL Audio, Inc.
10369 North Commerce Pkwy.
Miramar, FL 33025-3962
Phone: (954) 443-1100
Fax: (954) 443-1111

Website: www.jlaudio.com

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