The Fathom IWS (In-Wall Subwoofer) system features a one-of-a-kind design that provides a deep and rich bass experience. The IWS does this while remaining completely out of sight inside of the wall’s stud bay and without losing any of the subwoofer’s energy or causing unwanted rattles or vibrations. In order to achieve such a difficult task, a patented mounting system and grille assembly allow the strategically designed enclosure to “float” inside of the wall cavity. For optimum sonic performance and unwanted noises, there are a few key guidelines that must be adhered to during the Fathom IWS installation process.
Before installing the mounting bracket ensure that the stud bay is no less than 14-3/8” and no more than 14-7/8th” wide. The heart of the Fathom IWS installation is the mounting bracket and hanging rod. This patented design is what allows the enclosure assembly to “float” freely inside of the wall cavity.
As mentioned in our Ordering a Fathom IWS article, there are two different enclosure types. The “A-Enclosure” is tall and intended for 2x4 stud construction, while the “B-Enclosure” is shorter and thicker for 2x6 stud construction. Because of the enclosures’ difference in height, each enclosure uses a different hanging rod with a different length.
The mounting bracket must always be installed into the stud bay 90-1/2” from the bare floor, regardless of the size of enclosure and hanging rod that’s being used. This set height keeps the subwoofer in the ideal placement for optimum performance. 
Due to the acoustics of the room, moving the subwoofer higher up the wall will have a negative effect on the subwoofer’s overall performance. This also causes the emission of more energy in a section of the wall with less bracing and overall strength, which can lead to unwanted rattles and vibrations from the wall itself.
Each of the (5) enclosure options takes advantage of strategically placed foam padding in order to prevent the actual enclosure from making physical contact with any studs or drywall. When installing the mounting bracket, it is vital to use the included centering template for proper positioning. Once the enclosure is hung with the hanging rod, be sure to inspect the stud bay for proper clearance along the sides of the enclosure and verify that the enclosure itself (not the foam padding) is not sticking out of the stud cavity, which would interfere with the installation of the drywall. If the enclosure does not fit properly, consult a professional about any potential modifications that might be needed or check the other available enclosure sizes for a proper fit. You should be able to freely move the enclosure inside the stud bay once it has been hung.
The included foam gaskets for the faces of the studs are a key element of the install to help combat unwanted vibrations. They must be used prior to the drywall installation. A subwoofer that’s capable of handling 1,000 watts inside of a wall involves a great deal of energy, so the Engineering Team at JL Audio has taken all necessary steps in the design of the Fathom IWS system to combat vibrations or noises inside the wall cavity.
The grille assembly is the final piece that allows the enclosure to freely float in the wall cavity. The four screws on the outside of the grille assembly attach it to the studs. These are the only screws that should come in contact with any drywall or studs from the grille. The inner screw holes will mount the subwoofer to the enclosure through the grille’s bladder. This system allows the enclosure to remain floating and channels all of the subwoofer’s energy into the room.
The Fathom IWS is an innovative and one-of-a-kind system that takes advantage of JL Audio’s patented Thin-Woofer technologies, as well as multiple other patented technologies. However, if the IWS system is not installed properly, it may have a detrimental impact on the performance of the system as well as the walls of the room in which it’s installed.
For step-by-step directions, be sure to watch the video below or read the Fathom IWS Installation Manual.