JL Audio Fathom IWS-SYS-1 In-Wall Subwoofer System Review Page 2

After the installer secures an included adjustable mounting assembly between the left and right studs at 90.5 inches from the floor, the half-sphere on one end of an 11.25-inch-long “hanging rod” (26.25 inches for shorter/deeper enclosure variants) is inserted into a cup-like bracket attached to the mounting assembly. There’s a half-sphere on the other end of the rod and a simi- lar bracket on the top end of the enclosure. The installer lifts the enclosure, slides the free end of the rod into the enclosure’s bracket, and steps back to admire his work. Each end of the hanging rod can swivel somewhat in its respective cup mount—which means that gravity is ultimately what holds the enclosure in place. (At this point, JL doesn’t have plans for including a supply of gravity with the system, claiming, “It’s the customer’s responsibility.”)


Strategically placed spacers and padding on the exterior surfaces of the enclosure help prevent any hard contact between the enclosure and the wall structure. And the installation hardware includes a huge roll of “energy-absorbing foam gasket strip.” The installer applies this to the front edges of the studs and the mounting bracket to further minimize transfer of vibrations, something that’s particularly helpful with walls containing metal studs.









A Heavy-Mass Woofer
The subwoofer driver is JL Audio’s 13TW5v2. The fact that the diameter is 13.5 inches is unusual, but it pales in comparison to the amazing fact that the driver requires a mere 2.63 inches of mounting depth. JL calls the technology “Concentric Tube Suspension,” but it’s simpler to say it’s just a molded concentric tube structure that’s used to support both the spider and the driver’s large-diameter voice coil. (Well, maybe not so simple to say.) Basically, JL took a 7-inch-diameter voice coil—yes, 7 frickin’ inches!—and slid the magnet inside it rather than wrapping the magnet around the outside, as is found in typical loudspeaker drivers. The benefit is that, even though the overall depth is very shallow, the cone still has a great deal of excur- sion. It’s heavy and built like a tank—and although I’m not usually a fan of staring at drivers, I admit I was sad when I mounted this beautiful piece of audio engineering in the wall and put a grille over it.

Despite the laudable lengths JL Audio went to in order to minimize enclosure/wall vibrations, I expected that a resonating Achilles’ heel would be where the woofer met the wall. Ah, but this is where those extra install parts come in. After the enclosure is installed, the wallboard is replaced. A wooden template attached to the enclosure provides a guide for the wallboard guys to leave a square opening in the wall at precisely the location where the driver will hang in the enclosure behind the wall. It’s absolutely, excruciatingly important that the size, shape, and position of the opening are correct. Otherwise, the two parts of the grille assembly—the removable, paintable grille itself and the “grille tray unit”—won’t line up properly. They most definitely need to line up, too, because the grille assembly is the last bastion against vibration in the design of this subwoofer. As a matter of fact, alignment and placement are so important that JL makes three dif- ferent grille models, with depths to fit wallboards ranging from a half-inch to 1 9/16 inches thick.

I’ve never encountered anything quite like JL’s grille-assembly mounting system. The grille frame screws directly to the wall studs (through the wallboard)—not to the enclosure, as you might think. The grille tray unit includes a short, flexible sleeve that attaches to the grille frame on the outer side of the wall and extends inward, where, once the woofer is installed, it gets squeezed between the woofer’s flange and the enclosure. It’s like a sonic shock absorber that keeps the woofer/enclosure combo from touching the wall, and it acoustically seals the woofer itself from the in-wall cavity.

While the sub was burning in, I took advantage of the repetitive playback of a heavy bass track to check out these various isolation techniques. I had installed the sub in a normal, ordinary interior wall separating my home theater and a hallway, so while the sub was play- ing, I walked out into the hall. Not surprisingly, I could hear muffled bass coming from the room, and the wall was vibrating slightly—but nothing an in-room sub wouldn’t have also caused. The amazing thing was this: When I ran my hand along the wall of the hallway, spanning multiple studs, it was nearly impossible to tell where the sub was installed. Even more astonishing: As far as I could tell, there was a nearly equal amount of vibration along the wall on the left side of the door as there was on the right side, where the sub was installed. Those results made it well worth the time and effort involved in the installation.

Straight as an A.R.O.
Setting the acoustic parameters for the IWS-SYS-1 was almost a letdown. Everything stayed the same in my Onkyo TX-NR3030 A/V receiver except for the sub level, which I reset to 0, and all other tone controls and EQ functions were defeated. Then I plugged one end of the microphone cable into the mini-XLR jack on the front of the sub’s amplifier. After tripping once or twice over the cable, I attached the calibrated mic to the cable and set it up at my main listening position. The most difficult part was pressing the Calibrate button, waiting five seconds, and then enduring three minutes of a static- noise sequence. After that, I had to pack up the mic and watch a movie. (Exhausting, right?)


Unlike the room correction technologies from Audyssey and a few other companies, JL Audio’s A.R.O. calibrates only for the main listening position, not the entire room. (Nor does it affect audio coming from any of the other speakers in your system.) Want to judge the result against the sub’s sound without the optimization processing engaged? The Defeat button on the front of the amp makes it easy to do this. The changes that A.R.O. made in my room weren’t subtle. They were more of the significant, “welcome to the big leagues” kind of improvement. A.R.O. clarified the bass output, both taming it in the range from 40 to 50 hertz (where it had gotten out of hand pre-calibration) and giving it a kick in the butt in the low 20-Hz region. In short, pre-calibration, the sub sounded good—but not good enough to warrant $4,500 plus installation. It gave hints every now and then of greatness, but nothing sustainable over time. Post-calibration, on the other hand, the sub turned into a bad-ass bully of a bass beast—and I mean that in the best of all possible ways.

By the Bass of God
Now that you’ve read the previous paragraph, the results of my listening sessions won’t be too surprising. JL Audio’s IWS-SYS-1 sidles up behind you, begins whispering sweet bass love into your ears, and then morphs into a full-fledged bass-pumping Goliath (sorry, I mean, Fathom…er, giant thing…) that’s amazingly emotionally satisfying because, despite all the obvious power, the sub never loses control. The alt-metal beat of Disturbed’s “Indestructible” (along with the surreal battlefield soundscape at the beginning of the track) was made even more heavy metal because of the extreme low frequencies the sub could generate. The Decemberists’ “This Is Why We Fight” features a more agile drumming throughout the cut, and the sub easily kept up and stayed tight. My favorite track for the IWS-SYS-1 soon became “Big Shot” from Dr. John’s Grammy-winning Locked Down. The combination of Dr. John’s gravelly voice with the drums and bass—and damn well everything else in the track—was underpinned perfectly by the in-wall sub, which stayed as warm and as full as the music demanded without ever becoming boomy.

It’s somewhat ironic that the people who devised the audio for Deepwater Horizon were so metic- ulous in their work—acoustically re-creating the catastrophic results of what happened after some potentially disastrous work wasn’t done quite so meticulously. The IWS-SYS-1 handled the rig explosions exceptionally well, but I think what impressed me the most about the system while watching this movie wasn’t the depth of the bass output—although that was definitely impressive. It was the agility of the sub, especially the quick hits and thumps of the oil-drenched seabird as it frantically flopped around the inside of the control cabin, as well as the snap of the shrapnel that cuts through multiple scenes.


Although I had promised myself I wouldn’t watch Independence Day: Resurgence because the first movie was so stupid, I found myself sticking around for the whole thing because the IWS-SYS-1 was so compelling in its re-creation of the ominous mass of the alien mothership. This was quite spectacular during scenes where the ship begins drilling through the ocean floor. Similarly impressive was the sub’s ease in instantly going from nothing to seriously extreme bass any time the fusion drive was engaged. It seems silly to say, but the sub never sounded like it was in the room (or in the wall, for that matter). The bass was just another part of the experience, not unlike the couch I was sitting on, or the air I was breathing. It was seamless, yes, but that’s an easy word to use. It’s harder to describe the emotional and physical sensation created by the near-perfect entanglement of low frequencies, the listener, and everything else in the room. That engrossing interaction made the abrupt cuts between dialogue and blasts of heavy rap beats in War Dogs all the more intense, and it drew me into that movie much more than I had expected.

JL Audio’s $4,500 in-wall subwoofer system isn’t for everyone. There are some people who can peacefully coexist with the largest species of in-room subs. There are certainly plenty of people who can’t afford a $450 subwoofer, let alone one that costs 10 times that much. It’s hard to believe, but there are even human beings who don’t care about sound quality. Yet, for the demographic that has the financial means, desires the convenience of a nearly invisible subwoofer, and is serious about sound quality, the IWS-SYS-1 is an awesome choice. It’s a sub that makes no acoustic compromises, nor does it force you to make the lifestyle compromises that a typical in-room sub would. In some ways, it’s a shame that all the cool technology here is hidden from view—but, when you think about it, not seeing anything of this system is the coolest part of all. If you’ve got the money, and you’ve got a wall, this sub’s for you.

JL Audio
(954) 443-1100

thehun's picture

subs could be much cheaper and doesn't need much more extra to install one. Depending the number of woofers being used their output could be much more than this from a far smaller amp as well, and it could be calibrated from existing built in tools like Audyssey, etc...