13W6v2-D4: 13.5-inch (345 mm) Subwoofer Driver, Dual 4 Ω

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:
Since 1997, JL Audio has been at the forefront of Finite Element Analysis-based modeling of loudspeaker motors and suspensions. This research is aimed at decoding what we refer to as the "Loudspeaker Genome"... a project aimed at understanding the true behavior of loudspeakers under power and in motion. A major component of this integrated system is DMA (Dynamic Motor Analysis). Starting with the 15W3 and the W7 Subwoofers in the late 1990's and early 2000's, DMA has played an important role in the design of all JL Audio woofers sold today, including our component woofers.

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. This gives us a highly accurate model of a speaker's actual behavior under real power, something that the traditional Thiele-Small models or other low power measurements cannot do. 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. DMA not only shows that this "fixed" field changes in reaction to the magnetic field created by current flowing through the voice coil, but it helps our engineers arrive at motor solutions that minimize this instability. Analyzing this behavior is critical to understanding the distortion mechanisms of a speaker motor and sheds light on the aspects of motor design that determine truly linear behavior:

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
    

Our ability to fully analyze these aspects of motor behavior allows our transducer engineers to make critical adjustments to motor designs that result in extremely linear, highly stable dynamic loudspeaker motor systems.

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

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.

Our patented design improves upon this cooling technique in a number of ways. 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.

W6v2/W6v3 Terminal Jumper System

Summary:
Information on connecting the dual voice coils using the Terminal Jumper System

Detailed Information:
Please note that the W6v2/W6v3 is a dual voice coil driver. BOTH voice coils must be connected to the amplifier (in series or parallel) for the speaker to operate properly. To accomplish this, each W6v2/W6v3 features a pair of main input connection push terminals and four voice coil configuration tab terminals. These are located behind the main input connectors and are used to interconnect the dual voice coils in one of two ways:

Diagram A: Series Connection (8 ohm nominal impedance per speaker) Use one jumper from "VC1-" to "VC2+".

Diagram B: Parallel Connection (2 ohm nominal impedance per speaker) Use two jumpers... one from "VC1-" to "VC2-"and one from "VC1+" to "VC2+". This is the way the speaker is configured at the factory.
 
After verifying that the tabs are properly configured using the supplied jumper(s), connect the amplifier's output wires to the W6v2's main input pushterminals and install the speaker into the enclosure.
 
Warning: Failure to properly connect the configuration tabs will result in no output and may damage the speaker.

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. Our engineering team knew that high levels of cone rigidity would be needed, but they focused on achieving rigidity without a huge weight penalty. 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.

So why polypropylene? As stated above, our patented W-Cone technology achieves all of the benefits of more exotic materials while better suiting the unique nature of the W7. Since the W7 surround is detachable, the moving system (including the diaphragm) is subject to mechanical stress unseen in conventional designs. Because the user can tug on the cone while manipulating the surround, the cone must be able to handle this without buckling or deforming. Paper, metal or brittle composite cones would not handle this well. Our two-skin unit-body cone design achieves outstanding axial and torsional stiffness to withstand all kinds of abuse, and will remain largely unaffected and unblemished.

NeckVent™ Cooling (Patent Pending)

Summary:
Vents at the neck of the lower cone body work in conjunction with the pole vent's airflow to effectively remove hot air during high power operation.

Detailed Information:
The pole-vent works in conjunction with specifically engineered molded vents at the neck of the lower cone body to remove hot air from the voice coil gap. This improves power handling and linearity, leading to better sound quality and less power compression.

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.

Customizable Trim Ring

Summary:
This removable ring can be painted to match the installation theme and directly receives JL Audio grille mesh inserts (sold separately).

Detailed Information:
This ABS trim ring is molded in black, but that doesn't mean it has to stay that way. By custom painting it, you can match your installation theme and create a personalized look.

Specifically-designed grille mesh inserts are available separately and fit into the inner diameter of the trim ring.

Helpful Tip: Installing the grille mesh inserts is much easier before mounting the woofer into the enclosure.

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.

Detailed Information:
At a time when most audio products are built overseas, JL Audio’s commitment to in-house loudspeaker production continues to grow. To pull this off in a competitive world market, our production engineering team has created one of the world’s most advanced loudspeaker assembly facilities and established a global network of quality component suppliers who build to our specifications. This, combined with our commitment to state-of-the-art assembly technology, allows our skilled workforce to efficiently build JL Audio products to extremely high quality standards, right here in the U.S.A.

Since most of our premium loudspeakers incorporate proprietary, patented technologies requiring specific assembly techniques, we find it is vital that the people who designed them have close access to the people manufacturing them. The following JL Audio products are built in our Miramar, Florida factory, with global components:

• Subwoofer Drivers: W7, W6v3, TW5v2, TW3, TW1, W3v3
  
• Enclosed Car Subwoofers: Stealthbox®, PowerWedge™, ProWedge™, H.O. Wedge™ & MicroSub™ Enclosed Subwoofers
• Marine Loudspeakers, Marine Subwoofer Drivers and Marine Enclosed Loudspeakers
• Home Subwoofers: Dominion™, E-Sub, Fathom® and Gotham®