This review appears in the #1-2017 issue of Audio Esoterica magazine. The full text is below, but for a complete presentation we recommend clicking the image above or right to download a free PDF of the original article. You can see the full contents of this issue here, or to buy the complete digital edition of Audio Esoterica, click here.


Let’s be clear: subwoofers are not for everyone. For one thing, your loudspeakers may already plumb the bass depths quite to your satisfaction. Or you may not consider the really deep elements of the signal to be all that musically important. However, for some listeners, and I include myself here, high fidelity involves at least trying to reproduce everything that has been captured in the recording.

In the good old days, that was less of a challenge because the physics of grooves in vinyl precluded high levels of deep bass. With digital, not so much. If you do want that deep content, and your current speakers don’t quite do the job, then the JL Audio Fathom f112 v.2 subwoofer might be just what you need. Even more so two of them, which is what the Australian distributor provided for review.

These are monster subwoofers. But not in size – indeed in the general scheme of subwoofers these might be regarded as medium-sized, or even compact. But when it comes to weight… wow! Some 53 kilograms each is a lot of mass for boxes of this size.
And they are rather beautiful boxes, finished with a deep, lustrous black gloss all the way around. It seems almost a pity to stick them in corners rather than displaying them proudly in the middle of your listening room.

The enclosures are sealed and, as noted, also fairly compact. The subwoofer uses a high quality 300mm driver. Those three factors mean that as the driver cone moves to and fro, alternately rarefying and compressing the air inside the enclosure, the forces opposing the cone movement are enormous. So to work, JL Audio has provided a huge amount of power – up to 1800 watts is available. And it has built the enclosure to an astonishing level of rigidity. It is that which explains the weight.

The grille features a thick frame which clips onto four sturdy metal posts. It covers the front of the subwoofer completely, including the control panel at the top. The unit itself looks quite pleasing – to these eyes at least – with the grille off. The green power LED is quite bright with the grille removed, but a switch allows you to dim it or have it off.

Digital Signal Processing is integral to the operation of such a subwoofer. The f112v2 has an auto calibration system (the microphone and cable are provided in a pouch reminiscent of a school pencil case) which can tailor the performance to a specific position in the room.
There are both balanced and RCA inputs on the rear panel, accepting both stereo and mono inputs. The balanced inputs are dual-function XLR/TRS sockets of the kind found on a lot of professional gear. (TRS means Tip/Ring/Sleeve and is identical to a 6.5mm headphone connection except that the tip and ring are the signal and return wires, while the sleeve is for shielding.)

A switch is provided on the rear panel to lift the system from the earth should there be any hum problems. Another switch selects between Master and Slave operation. You can daisy-chain up to ten of these subwoofers together. The first one is the master and its DSP controls all proceedings, while the others in slave mode are kind of naive, doing no signal processing and with their various controls locked out, leaving all processing to the DSP in the master subwoofer. All the regular controls are at the top of the front panel, making for easy access.

Installation Considerations
So what’s the best way of connecting two identical subwoofers in a system? Depending on your equipment, you might have a decision to make. Remember, there are no speaker-level inputs for these subwoofers.

Ideally, especially in a stereo system, you will employ a high-quality stereo active crossover between pre and power amps. In other cases you might be using a high quality home theatre receiver or processor to perform the crossover work. Either way, should you use both subwoofers in “Master” mode and tie each to the left or right channel? Or should you slave one to the other and employ a mono bass signal?

Most home theatre devices only offer the latter option. Even those with twin subwoofer outputs usually provide them merely as a convenience – they carry the exact same signal. But what if you do have the choice? All the theories of human hearing suggest that there’s no advantage to going stereo, so long as the bass is below a hundred hertz or so. If your equipment gives you the option, I’d recommend trying both.

JL Audio Fathom f112v.2_rearThe equilateral triangle relationship between speakers and listener isn’t quite so critical with subwoofers, because the wavelengths of bass frequencies are quite long. At 120 hertz (the uppermost frequency delivered by the LFE channel, and well above any frequencies redirected from the main channels) a quarter wavelength is over 70 centimetres. So if both subwoofers are the same distance from the listening position within about 20 centimetres, then there won’t be any problems. But these subwoofers have a ‘phase’ control which is actually a group delay control (the timing is based on a phase shift at 80 hertz). These should be adjusted anyway for ideal matching with the main speakers, but the close one can have the sound delayed slightly more, to match it with the further one. Ninety degrees is just about the same as a one metre delay.

Now, given the power and performance of the Fathom subwoofers, why would one want more than one? There’s no doubt that one will do the job in most circumstances, but here’s the thing. Bass harmonic distortion is in part a function of cone excursion. The bigger the cone, all other things being equal, the less the distortion. Two subwoofers mean twice as much cone, which means significantly less distortion.

The Digital Automatic Room Optimization system is exceptionally easy to use. You plug in the microphone lead, press the calibrate button, dash back to your seat and hold the microphone where your head is. Then wait three minutes while the test tones are run and the system does its work. The only thing I’d dispute about the manual’s description of the process is that the tones sound absolutely nothing like ‘hashy static’. The first two-thirds sounds like a major earthquake, and then it lightens up a little towards the end. You may want to run through the calibration a few times. Tracking down the rattles in your room as it runs each time and moving objects, or gluing them down. I can guarantee that this subwoofer – let alone two of them – will reveal every loose fitting in your room. When your room is finally rattle-free, do the calibration again for the last time.

With one subwoofer slaved to another, the procedure is no different. Only one calibration is performed and the DARO system adjusts the 18-band (!) equaliser to deal with the sound at the listening position, regardless of how many speakers are producing it. If running two subs as separate left and right units, then both will be in Master mode, and both should be calibrated independently.

Oh, if you have any doubts about whether the EQ (it’s all done via DSP, so the horrors of old-fashioned EQ are neatly avoided) is worth it, there’s a ‘Defeat’ button on the front panel, right next to the ‘Calibrate’ button, so you can switch it on and off to determine which you’d prefer. For me? Oh, yes, yes, yes. Unfortunate room modes were wiped out. Bass guitar scales actually became even in level, rather than variable according to note.

There’s one manual adjustment for tone too. It’s a small knob called ‘E.L.F. Trim’ and you can use it to boost or cut the deep bass (from +3dB to -12dB at 24Hz). This may be useful if you employ the services of a professional calibrator who can measure the response.

In Use
For those who regard the really deep bass as dispensable, I’d suggest grabbing some of the great Bach organ works and try listening with and without. Bach was not reluctant to use the pedals in his music. The Passacaglia and Fugue in C minor (Stokowski characterised this as the ‘most sublime’ piece of music ever written) finishes each section on the bottom C pedal available on the instrument. On Telarc’s recording using the Great Organ at Methuen (with its 6000-plus pipes), the fundamental frequency of that note is 16 hertz. On lesser but still large organs it’s 32 hertz. And unlike a piano, that C produces a lot of energy at 32 hertz, especially given the hall itself becomes part of the instrument.
These subwoofers couldn’t quite reach that 16 hertz, but they filled the listening room with a near infrasonic energy conveying that space, making my listening room a hall in Massachusetts with a 20-metre high ceiling, the other dimensions similarly generous. There’s something about very deep bass, just on the edge of one’s levels of perception, which acts on one’s sense of where one is and what one’s surroundings are. These subwoofers delivered that without reservation.

And as each section concluded its descent through the C minor scale to the deepest bass note, the whole room throbbed as it does with a real organ in a real church (the Methuen hall isn’t a real church, but is built to sound like one).

More prosaically, a subwoofer combined with high quality compact speakers – we used models which perform beautifully to below 60Hz – provides music in which your fine speakers are relieved of the burden of capacity-sapping deep bass. The sound produced by these subwoofers integrated so well into the main speakers, it was as though they were part of those very speakers.

We ran through a variety of recordings in a wide range of genres, including gorgeously recorded jazz works from Blue Coast Records on DSD, then pop and rock into some fairly hard stuff, and the result was the same with all: a combination of these subwoofers delivering an appropriate bass underpinning the work of the main speakers, closely matched in timing and tone, but with a seeming limitless ability to reach any crescendo required by the music. With, for example, the relatively sparsely recorded tracks of Side 2 of Synchronicity by The Police – “Wrapped Around Your Finger” and “Tea in the Sahara” in particular – the fundamental tones of Sting’s bass guitar were as one with the upper harmonics, with no sense of separation between the frequencies delivered primarily by the sub and those by the main speakers. The timing was impeccable. As it was with faster material, such as the self-titled album from Rage Against the Machine (oh, that opening riff of “Bullet in the Head”!). The overblown bass of this recording was tamed a little by the very smoothness of these subwoofers acting in concert, without detracting from the slam and rhythm of the material.

These are just tastes of what is available here. Smooth, deep and powerful bass without any reasonable limit. And, you know, your smaller monitors, being in their own enclosures, remaining on their own stands or otherwise in their own positions, retain their character. It’s just that they have an octave or two underpinning their performance.

Oh, before I finish: yes, it almost goes without saying that these subwoofers do a superb job at home theatre as well. Some manufacturers seem to think that there’s some fundamental difference between the two functions. But there isn’t if you want any kind of quality. A cheap home theatre subwoofer can fake it by delivering bits of the bass, the frequencies it can handle, to give the impression that the low frequency effects are there. All that falls apart with music of course. But a highly musical subwoofer of sufficient power can do home theatre with the best of them. This subwoofer is up there with the best of them.

In short, if you’re after high performance subwoofers that will deliver the bass you might
presently be lacking, smoothly and powerfully, then you must audition the JL Audio Fathom
f112 v2 subwoofers.

JL Audio Fathom f112v2
Inputs: 1 × analogue stereo (balanced XLR/TRS), 2 × analogue stereo (RCA)
Outputs: 1 × pass-through to slave subwoofer (balanced XLR)
Driver: 300mm
Frequency response: 21Hz-119Hz ±1.5dB; -3dB at 19Hz and 150Hz; -10dB at 17Hz and 167Hz
Amplifier power:1800 watts short term
Dimensions (WHD): 384 × 470 × 451 mm
Weight: 53kg
Warranty: Two years
Price: $6495 each

POSTCRIPT: When using a subwoofer it's important to ensure correct integration of that subwoofer's output with that of your main loudspeakers by setting the subwoofer's volume, phase and crossover frequency controls correctly. You can read an article on a simple, effective method of how to do that HERE.