Subwoofer Reviews

It was all so familiar. In "Music in the Round" in the January 2016 issue, Kal Rubinson praised JL Audio's latest subwoofer, the Fathom f113v2. He raved about its amplifier's higher power over the original f113, its beefier 13" woofer, its improved, 18-band Digital Automatic Room Optimization (DARO), and its significantly improved deep-bass response in-room.

It was familiar because the same thing had happened when Kal reviewed the original Fathom f113 in his May 2007 column. As he would again nine years later, he'd extolled the sub's high power, small size, built-in single-band Automatic Room Optimization (ARO) software, and "remarkably powerful and clean" deep bass. Those were also my reactions to the Fathom f113.

One thing led to another: I reviewed the Fathom f113 in the September 2007 issue, and the larger Fathom f212 in the April 2010 issue, both in pairs. The two Fathoms impressed me with their bass extension, powerful impact, dynamic range, and ability to significantly increase the depth and width of the soundstage.

Which was why, after reading Kal's January 2016 column, I called Carl Kennedy, JL's VP of sales. I had to hear a Fathom f113v2 in my own system. Kennedy must have been expecting my call. "No," he said, "Kal has already done the Fathom f113v2s; I'd rather you reviewed a pair of Fathom f212v2s."

Be careful what you wish for: heavier Fathoms
Within a month, JL Audio had shipped me two Fathom f212v2s and their new CR-1 outboard crossover—total weight over 512 lbs—secured with thick metal straps to a large wooden pallet. No tool in my house could dent those straps, so I picked up a set of 18-gauge Wise W2 aviation snips at Home Depot. Their steel blades cut the thick metal straps as if they were butter. I carefully nudged the shipping cartons off the pallet and onto the garage floor.

That was the easy part. Try as I might, I couldn't move either 256-lb speaker carton anywhere: the f212v2s stayed put as if welded to the floor. Several phone calls later, two young, muscular handymen arrived, schlepped the huge cartons upstairs, and unpacked them in my listening room. I slipped the four supplied Waxman Super Sliders under each sub to protect my wood floors, then slid them into the room's front corners—the sweet spots where the two review samples of the first version of the Fathom f212 had sat.

What's new
Looking at the Fathom f212s, I was hard-pressed to see any differences between v1 and v2 that might justify the $1000 increase in price, to $7000. The changes are within. The v1's single-band ARO equalizer has been replaced with JLA's 18-band DARO, which covers the range from 20 to 150Hz. Kal Rubinson described DARO performing "cut-only correction, with automatic output level realignment post-EQ. Each band is adjusted independently by the DSP. In addition, microphone gain and output levels are adjusted automatically, without user effort, which results in greater ease of use and, more important, more accurate and consistent results."

Audio line-level signals are now directed to circuit boards inside a cast-aluminum housing attached to the inside of the f212's rear panel—they're never routed to the control panel directly. The f212v2's class-D internal amplifier is 20% more powerful (3600W short-term) than the v1's, which required JLA engineers to thicken the roll surrounds of the woofers to maintain their linearity and low distortion.

The Fathom f212v2's build quality doesn't disappoint. It's a massive, super-solid sub with a lustrous, High Gloss finish, equipped with high-quality Neutrik balanced connectors. All mechanical controls are of the set-and-forget type, and feel smooth and solid to the touch. The fit'n'finish are outstanding—this sub should last a lifetime.

CR-1 outboard crossover
Most aftermarket subwoofers depend on the high-pass 80Hz crossover filter built into A/V processors. But audiophile-quality two-channel preamplifiers don't include crossover filters for the same reason they don't have tone controls. Thus, for those with music-only systems, an outboard crossover becomes a necessity for the optimal integration of a subwoofer—it's not an optional accessory.

The $3000 CR-1 meets this need. Its continuously variable high- and low-pass filters (30–150Hz) use 1% precision JFET-input op-amps, and polypropylene film and foil capacitors to "optimize the audio system's spatial and spectral performance." The low- and high-pass circuits are built around two banks of precision Linkwitz-Riley filters that can be set for 12 or 24dB/octave via a front-panel switch. Differential input technology is used to reject common-mode hum and noise on the unbalanced inputs, and independent buffering of the balanced and unbalanced outputs reduces the likelihood of noise. The rear panel offers both balanced (XLR) and unbalanced (RCA) connectors.

The CR-1's front-panel controls are a pleasure to use. Bypass switches are prominently featured. According to Brett Hanes, JLA's lead engineer for home products, "you can listen to the satellites in full-range (no filters applied and no subs) by hitting the CR-1's Bypass button (its LED goes from green to red). Dealers use this one-button 'bypass demo' on the CR-1 as a teaching tool to easily show potential customers what a difference a subwoofer can make in their stereo system." Indeed, being able to switch quickly, without having to detach and reinsert interconnects, helped me by speeding setup time between comparisons—important because auditory memory is so short. Four Output Muting pushbuttons on the right of the CR-1's front panel can individually shut off each of two main speakers and each of two subs (if a button's LED glows red, that speaker is not playing).

Setup
I set up each Fathom f212v2 without its protective grille, and with its front baffle 2.5' behind the front baffle of the corresponding Revel Ultima Salon2—a full-range, dynamic, floorstanding speaker. The inner edges of the Salon2s' baffles were 8' apart, their outer edges 3' from the sidewalls, and the centers of their baffles 7' from my ears when I was seated. Both subs' woofers were 9.5' from my listening chair.

With the exception of the CR-1 crossover, I used the same system connections I had for my review of the original Fathom f212 in 2010. I ran balanced interconnects from my Bryston BP-26 preamplifier's outputs to the CR-1's inputs. Another pair of balanced interconnects linked the CR-1's low-pass outputs to each f212v2's left-channel input jack, with each subwoofer's rear-panel switch set to Master. More balanced interconnects linked the CR-1's high-pass outputs to the inputs of my Mark Levinson No.334 power amp, which was connected to each Ultima Salon2 with Pure Silver R50 biwire double-ribbon speaker cables.

Measurements
For this review, I used Studio Six's iTestMic—a cost-effective, professional-grade test and measurement microphone that plugs into my iPhone 6—plus Studio Six's Audio Tools app to run fast Fourier transform (FFT) frequency-response measurements from 8Hz to 2kHz. I placed the iTestMic–iPhone 6 combo on the back of my listening chair at ear level: 37" above the floor. For a test signal, I used a digital file of uncorrelated pink noise, played through my Bryston BDP-2 media player.

I first put the CR-1 on full Bypass, to run FFT measurements on the Salon2s full-range, without crossover filters or subwoofers. This generated a flat room-response curve: ±3dB, 8Hz–2kHz (fig.1). To run the Fathom f212v2s solo and full-range without crossover, I plugged the Bryston preamp's balanced interconnects into the CR-1's Bass Management inputs, and depressed the Defeat button on each sub's control panel to bypass its internal settings. The resulting FFT showed an irregular room response: ±6dB, 18–125Hz, with a peak at 45Hz and a bigger null at 60Hz (fig.2).