Product overview
Low distortion, excellent dynamic capabilities and shockingly deep bass extension will allow you to experience all the excitement of the most demanding cinematic material, while also being able to reproduce all the nuance and texture of your most delicate musical material.

A complete set of signal processing features is easily accessible on the front surface of every Fathom. These include a highly flexible low-pass filter, variable phase, switchable polarity, e.l.f. trim and our powerful Digital Automatic Room Optimization (D.A.R.O.) system. A calibrated microphone is included for the D.A.R.O. system. Input connections are made via unbalanced RCA connections or balanced Neutrik® combo XLR/TRS jacks. Also included is an XLR output to connect a second Fathom® as a slave unit.

Technology

Digital Automatic Room Optimization (D.A.R.O.)

Summary:
JL Audio's exclusive D.A.R.O. technology uses a powerful on-board DSP to automatically optimize the subwoofer's in-room frequency response. This leads to a superb listening experience, no matter where the subwoofer is placed.

Detailed Information:
In typical listening spaces, subwoofer and listener placement have a profound effect on the accuracy of low-frequency reproduction. In the real world, subwoofer placement almost always involves a compromise between sonic performance, practicality and aesthetics.
To face this dilemma head on, JL Audio subwoofer systems incorporate a clever piece of technology called Digital Automatic Room Optimization (D.A.R.O.). The D.A.R.O. system self-generates a series of calibration tones, measures the frequency response at the listening position, and automatically configures an 18-band, 1/6 octave equalizer for a flat end-result. The system effectively allows for smooth, well-balanced sub-bass from a variety of locations that would have been less than ideal without D.A.R.O.

To perform this audio magic, all you have to do is:

1. Connect the included calibration microphone to the front panel of the subwoofer.

2. Press the calibrate button on the front panel of the subwoofer.

3. Hold the microphone at the primary listening position for about a minute.

4. A few minutes later, you have completed this one-time setup routine.

You won't need a computer, spreadsheets or complex measurement equipment, and you won't need to navigate and manipulate complicated interfaces… D.A.R.O. is a fine example of technology in the service of man, if there ever was one.

Dynamic Motor Analysis - DMA Optimized Motor

Summary:
JL Audio's proprietary Dynamic Motor Analysis system is a powerful suite of FEA-based modeling systems, first developed by JL Audio in 1997 and refined over the years to scientifically address the issue of speaker motor linearity. This leads to vastly reduced distortion and faithfully reproduced transients... or put simply: tight, clean, articulate bass.

Detailed Information:

DMA is a Finite Element Analysis (FEA)-based system, meaning that it takes a large, complex problem, breaks it down into small solution elements for analysis and then assembles the data to form an accurate, "big-picture" solution. DMA's breakthrough is that it actually considers the effects of power through the coil as well as coil/cone position within the framework of a time-domain analysis. Because DMA does not rely on a steady-state model, it is able to consider shifts in the circuit elements being analyzed. These modeling routines are intense, requiring hours to run for a whole speaker.

DMA is able to analyze the real effects of fluctuating power and excursion upon the magnetic circuit of the motor, specifically the dynamic variations of the "fixed" magnetic field. This delivers intensely valuable information compared to traditional modeling, which assumes that the "fixed" field produced in the air gap by the magnet and the motor plates is unchanging.

1. Linear motor force over the speaker's operational excursion range

2. Consistent motor force with both positive and negative current through the coil

3. Consistent motor force at varying applied power levels

The payoff is reduced distortion, improved transient performance and stellar sound quality.

W-Cone (U.S. Patent #6,496,590)

Summary:
The W-Cone is a unit-body cone assembly that delivers astonishing cone stiffness with minimal mass. The shape also provides superb torsional rigidity, which is critical to maintaining voice coil alignment at the suspension limits.

Detailed Information:
The more excursion and motor force a speaker has, the more important cone rigidity becomes. The acceleration forces are extreme, requiring the cone to withstand rapid changes in speed and direction without deformation. Deformation not only leads to distortion, but can also affect the speaker's mechanical integrity by allowing the voice coil to go out of alignment and rub on the top-plate and the pole-piece of the motor.

There are several approaches to enhancing cone rigidity. The obvious ones are using a thicker material and/or a stiffer material. In recent years, several manufacturers have used composite cone materials (Kevlar®, fiberglass, etc.) or metals (aluminum, magnesium, titanium alloys). The use of these exotic materials is typically accompanied by marketing claims that the material chosen has exceptional stiffness-to-mass characteristics. These are true statements, but can be misleading. While these materials have excellent stiffness-to-mass properties (compared to paper or poly), they are not lighter than paper or poly in practice. This means that their use accepts the compromise of added moving mass on the design. This leads to efficiency penalties and suspension complications (it's harder to keep a heavy mass aligned properly).

A simple poly cone diaphragm, while sufficient for lower power designs, would not remain rigid under the demands that the W7 design requires. This ultimately led to the design we call the W-Cone. The W-Cone assembly achieves its rigidity through architectural means, rather than through inherently stiff materials. The design addresses the stiffness issue by using two lightweight mineral-filled polypropylene skins, bonded together at the perimeter and the center of the assembly. The lower skin's cross-section is shaped like a 'W', hence the name, and provides incredible rigidity when bonded to the dished upper skin. The effect is not unlike the trusses of a bridge or the unit-body construction of a modern automobile. In addition to the overall rigidity benefit, the lower skin's shape distributes the force generated by the coil and motor more evenly than a typical diaphragm. The force is not only applied to the apex but also distributed to the perimeter of the outer diaphragm for more linear behavior. A further benefit of the W-Cone is that the upper skin (the one in contact with the listening environment), is isolated from the high air-pressure gradients of the enclosure, further reducing deformation (and distortion).

As a point of comparison, the W-Cone assembly of a 12W7 is 32% lighter than a typical aluminum-alloy 12-inch cone. If analyzed in terms of weight per square inch of piston area, the W7 cone-body weighs 1.24g/sq.in., compared to 1.45g/sq.in. for an aluminum-alloy cone and 1.66g/sq.in. for a titanium-alloy cone.

Elevated Frame Cooling (U.S. Patent #6,219,431 & #6,229,902)

Summary:
JL Audio's patented Elevated Frame Cooling design delivers cool air through slots directly above the top-plate to the voice coil of the speaker. This not only enhances power handling, but also sound quality by minimizing dynamic parameter shifts and power compression.

Detailed Information:
Many speakers employ venting techniques to enhance voice coil cooling. This is typically accomplished by having big holes in the sides of the frame just below the spider attachment shelf. While it provides a modest cooling benefit, this low-velocity air-flow does not blow directly or strongly on the voice coil.

By elevating the frame above the top-plate of the motor (via stand-offs integrated into the bottom of the frame) a narrow, high-velocity air-path is created between the bottom surface of the frame and the top surface of the top-plate. This air path leads directly to the voice coil and then turns upward into the spider air cavity. By utilizing the pumping action of the spider through this focused air path, a large volume of cool air hits the coil windings directly.

Another important benefit is that the upper surface of the top-plate (one of the speaker's hottest parts) is directly exposed to cooling air flow, whereas on a conventional design it is isolated from the air flow by the lower flange of the frame. The elevated frame technology greatly increases thermal power handling, reduces compression effects and does so without any additional parts.

Floating Cone Attach Method - FCAM™ (U.S. Patent #6,501,844)

Summary:
This assembly technique, conceived by JL Audio, ensures proper surround geometry in the assembled speaker for better excursion control and dynamic voice coil alignment.

Detailed Information:
JL Audio's patented FCAM™ technology is an innovative method of bonding the surround/cone assembly to the voice coil former/spider assembly. This feature helps ensure concentricity of the surround, spider and voice coil without torquing the suspension to achieve it. This allows for the inevitable, slight variations in production part dimensions without having them negatively impact the integrity of the suspension and coil-centering at high excursions.

OverRoll™ Surround

Summary:
By utilizing space wasted in conventional speakers, this ground-breaking innovation controls the W7's massive excursion without sacrificing precious cone area.

Detailed Information:
One of the first things you notice about a W7 is that something is "missing"... the mounting flange. Of course, this is actually not the case. The mounting flange is simply hidden beneath the surround and is made accessible for mounting purposes by detaching the outer edge of the surround and moving the roll to the inside (a pretty neat little trick). Apart from the obvious benefits of amazing your friends as you pull the surround off your speaker, there is a serious technical issue that led JL Audio in this design direction: Effective Piston Area ("Sd"). This is essentially the speaker's "cylinder bore", to use an automotive engine analogy, and is calculated by measuring the diameter of the diaphragm including one-half of the surround roll-width. In other words, from the top-center of the surround on one side to top-center of the surround on the other side.

The displacement capability of a speaker is determined by this piston area times the speaker's excursion capability. Displacement of air is directly linked to output potential. Therefore, the more air a speaker can ultimately displace, the louder it can play. That being said, there is a big difference between piston area and excursion: piston area doesn't need power to make it happen. This means that by making a larger piston, you are directly improving displacement for a given amount of excursion and, therefore, making your speaker more efficient. This is not the only factor that governs efficiency, but it is a major one.

To make a speaker have more excursion capability not only requires a motor design that can deliver more stroke, but also requires a surround rugged enough to handle the demands of longer excursions and controlled enough to keep everything lined up properly. If the surround's roll-width is not adequately large, its behavior (compliance) is not linear over the useful stroke of the woofer and it is more likely to fatigue and fail. For this reason, speakers with longer excursion capability generally need larger surround rolls.

The problem with big surrounds is that they begin to encroach on the effective piston area of the driver. For example, a typical 12-inch woofer with a medium-sized roll has an effective piston area of 81.52 square inches. Compare this to a fat-surround 12-inch woofer which has a piston area of 69.07 square inches (15.2 % less effective piston area than the medium-size roll.) To overcome this loss, the fat-surround woofer has to produce more excursion to displace the same air as the woofer with the medium surround (and will require more power to do so).

The technology also provides a geometry advantage on the outside edge of the surround roll, allowing for more linear operation. A further benefit is that the mounting holes are inherently sealed by the surround, resulting in an improved box seal.

Radially Cross-Drilled Pole-Piece (U.S. Patent #6,243,479)

Summary:
This innovative venting system greatly enhances thermal dissipation and power handling by directing air flow onto the voice coil former, working in conjunction with the Elevated Frame cooling technology to effectively remove heat from the voice coil. This improves power handling and reduces power compression effects, leading to more linear performance.

Detailed Information:
This technology differs from a conventionally vented pole-piece in that the air flow is capped off at the top of the pole-piece and directed through machined holes on the outer wall of the pole-piece to the region directly behind the voice coil. The top portion of the pole-piece is smaller in outside diameter where the holes vent and helps create a high-volume, high-velocity airflow path between the inner-coil cavity and the ambient air of the enclosure.This helps remove super-heated air that is trapped between the coil former and pole-piece on a conventional design, leading to a dramatic improvement in cooling efficiency, especially at high excursions.

Engineered Lead-Wire System (U.S. Patent #7,356,157)

Summary:
Carefully engineered lead-wire design and attachments ensure controlled, quiet lead-wire behavior under the most extreme excursion demands.

Detailed Information:
Managing the lead-wires on a long-excursion woofer is one of the trickier aspects of its mechanical design. To address this, many long-excursion woofers today rely on a simple solution that weaves the lead-wires into the spider (rear suspension) of the driver.

The biggest problem with this approach is that spider limiting behavior plays a hugely important role a woofer's performance. Lead-wires that are attached or woven into the spider material can alter the spider's "stretching" behavior. The tinsel wire naturally has less 'give' than the fabric material of the spider leading to asymmetrical spider behavior and non-uniform stress distribution around the spider circumference. The wire attachment points can also cause localized pulling and tearing forces at the spider's excursion limits. As such, longevity becomes a major concern and makes the woven-in design less than ideal for very long-excursion designs.

While a traditional 'flying lead' design does not compromise spider linearity or radial stability, it creates its own challenges on a long-excursion woofer. Managing the 'whipping' behavior of the wire and making sure it does not contact the cone or spider is one challenge. Another is ensuring that the leads do not short one another or the frame of the woofer.

To overcome these issues, JL Audio's engineered flying lead-wires work in conjunction with carefully engineered entry and exit support structures molded into the terminals and the voice coil collar. Some models also feature jacketed lead-wires to further reduce the likelihood of shorting and fatigue. The result is flawless high-excursion lead-wire behavior, with outstanding reliability and none of the compromises inherent to a woven-in lead wire system. Building woofers this way requires much more labor and parts complexity than the simpler woven-in approach, but the payoff is in reduced distortion, reduced mechanical noise and improved reliability.

High-Damping Feedback Circuitry (U.S. Patent #6,441,685)

Summary:
This proprietary, discrete control circuit design allows our Class D switching amplifiers to maintain an excellent damping factor for improved transient behavior and fidelity.

Detailed Information:
While Class D amplifiers are well known for outstanding efficiency, they have also been known for less than spectacular sound quality due to weak damping of the driven load and poor power regulation. These factors are critical to subwoofer fidelity as they relate directly to the amplifier's ability to control the motion of the speakers.
JL Audio's Patented Class D output circuit utilizes a discrete control section and a unique feedback loop design that results in outstanding power regulation with a damping factor that's vastly higher than other Class D designs and also higher than most Class A/B amplifiers. The benefit of this exclusive JL Audio technology is tight, clean bass reproduction with the efficiency advantage of Class D.

It is a package tailor-made for world-class bass performance.

Built in U.S.A. with Global Components

Summary:
JL Audio's Miramar, Florida loudspeaker production facility is one of the most advanced in the world.