W-Cone: The JL Audio W7 subwoofer utilizes a W-Cone design, a
unit-body cone assembly, that delivers astonishing cone stiffness with minimal
mass. The shape also provides incredible torsional rigidity, which is critical
to maintaining voice coil alignment at the suspension limits. In order to gain
maximum stiffness, two lightweight mineral-filled polypropylene skins are bonded
together at the perimeter and the center of the assembly. The lower skin's
cross-section is shaped like a "W", and provides incredible rigidity when bonded
to the dished upper skin.
OverRoll Surround: OverRoll Surround technology allows JL Audio to
make full use of the entire footprint of the speaker, placing the surround
further to the outside than in a conventional woofer. This means that W7
subwoofer can use a large roll for all its benefits without sacrificing cone
area. By maximizing the effective piston/total footprint ratio, the W7 subwoofer
can deliver more output for a given excursion and outside frame diameter. This
means that the prodigious excursion advantage of the W7 can be put to full use
enhancing output, rather than making up for lost piston area. This 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.
Dual Voice Coil: Due to the 13W7's dual 1.5 ohm coils, there is
greater amplifier application flexibility. The speaker may be configured as a
0.75-ohm woofer (coils in parallel), a 3 ohm woofer (coils in series), or it can
be driven by two amplifiers, each driving one 1.5 ohm voice coil).
Ultra-Long Voice Coil: The W7 subwoofer features an ultra-long voice
coil to allow extreme linear excursion, phenomenal power handling and control.
The massive surface area of these coils is excellent for heat dissipation, while
the huge winding height provides the necessary motivational force to achieve the
huge excursion of the W7 designs. Considering their size, the W7 voice coils are
extremely light in weight. The W7 uses aluminum-alloy wire (instead of
conventional copper) and a specific winding method to achieve JL Audio's desired
electrical properties. The light weight of the coils helps keep the overall
moving mass down at manageable levels, which is extremely important for
efficiency and sound quality reasons.
Floating Cone Attachment Method (FCAM): JL Audio's patented FCAM
technology is an innovative method of bonding the surround/cone assembly to the
voice coil/spider assembly. This assembly technique ensures proper surround
geometry in the assembled speaker for better excursion control and dynamic voice
Dynamic Motor Analysis (DMA): DMA is JL Audio's proprietary method
aimed at improving dynamic motor behavior. As a result of DMA optimization, W7
motors remain linear in motor force over a very long range of excursion, and
also maintain a highly stable fixed magnetic field in the gap over a wide power
range. The result is vastly reduced distortion, faithfully reproduced
transients, and tight, clean, articulate bass.
Massive Forced Air Cooled: The elevated frame design of the W7
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.
Radial Cross-Drilled Pole Piece: This innovative venting system
greatly enhances thermal dissipation and power handling by directing air flow
onto the voice coil former and works 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
Progressive-Roll Spider: The large, progressive-roll spider provides
precise control and motor/voice coil alignment without limiting excursion
Plateau-Reinforced Spider Attachment: The lower reinforcement collar,
attached to the voice coil former of the W7, incorporates a plateau design
dedicated to relieving material stress and providing a solid attachment surface
for the inner edge of the spider. The plateau of the reinforcement collar
provides excellent contact area for adhesive therefore creating an incredibly
strong bond at a critical point within the driver.
Co-Extruded Double Lead Wires: The extruded casing and carefully
engineered attachments ensure controlled lead-wire behavior under the most
extreme excursion demands. Two conductors are used per connection for ample
current carrying capability.
Recommended Sealed Box Volume: The sealed box size recommended by JL
Audio is 1.875 cu/ft. A diagram is provided in the owner's manual for a sealed
box with external dimensions of 17" W x 17.25" H x 16.5" D, assuming 3/4" thick
material for the top, bottom and sides of the box and 1" thick material for the
front baffle board. (If you are using 5/8" thick materials, you should subtract 1/4" from
Recommended Ported Box Volume: The ported box size recommended by JL
Audio is 2.375 cu/ft. A diagram is provided in the owner's manual for a sealed
box with external dimensions of 25.125" W x 17.25" H x 16.5" D,
assuming 3/4" thick material for the top, bottom and sides of the box and 1"
thick material for the front baffle board. (If you are using 5/8" thick materials, you should subtract 1/4" from
each dimension.) A slot port is recommended with the following dimensions:
- Slot Width = 2.0"
- Slot Height = 15.75"
- Slot Length = 25.375" (a right angled port with a 7.875" extension)