It's always a pleasure for me to review a product from JL Audio. I not only know many of the "players" at JL Audio personally, but I have a tremendous respect for its engineering. Unquestionably, JL Audio is on top of the list of the brands that come to mind when you talk about car audio subwoofers. The company has been specializing in car audio products since 1975 (national distribution of JL Audio's subwoofer line started in 1992), and has long been considered a top contender among subwoofer manufacturers. It has developed an enviable reputation for not only building a quality product but has released a constant stream of serious no-nonsense subwoofer innovations over the years. It was among the earliest companies to use layered voice coil windings beyond four layers, and its patented vented reinforcement collar (VRC) that greatly strengthens the critical bond between the voice coil former, spider and cone is impressive. I know a lot of companies and a lot of engineers in car audio and I would have to say that JL Audio is certainly on the short list of the manufacturers I consider to be truly professional at what they do. Much like the JL Audio 10W7-3 I reviewed last year, the recently released W6v2 series brings on yet another batch of interesting and patented technologies.
If the W7 woofers are JL Audio's full-tilt boogie statement describing the best performing subwoofer it could envision, then the W6v2 series is its attempt to take that showcase product and make it a little more affordable. While the W6v2 series could be considered a step down, my first impression is that it's not a really that big of a step. For starters, the W6 is built with a very similar frame as the W7 and incorporates the same Elevated Frame cooling technology. While the W7 woofers have six sets of split spokes, this frame has five sets and attaches to the front plate and motor system with adhesive and five bolts, one for each dual spoke section. In between these connection points are the five 2 x 11/48-inch vent holes (see Figure 1, pg. 86). Since these are located at the top of the front plate, they encourage airflow across the motor top plate with the air immediately surrounding the exposed forward moving end of the voice coil. All this cooling technology is aimed at keeping the operating parameters of a woofer as stable as possible over its entire dynamic range.
The motor (the thingy you probably refer to as the magnet) of the JL Audio 12W6v2 uses a large, single 167x40mm ferrite magnet. This is unusual as most large magnet motor systems typically employ a series of either two or three stacked magnets. This gonzo magnet is sandwiched between a forged 9.5mm-thick front plate and a single piece T-yoke. JL Audio employs a lot of science in developing a motor system like this. All of the current technologies, such as the laser-based, non-linear analysis tool called the Klippel Analyzer, an FEA program named CosmosM for modeling thermal dynamics of a woofer, and Maxwell for magnetics, were obviously made use of. The company has also developed its own proprietary modeling software called DMA, for Dynamic Motor Analysis. This powerful software is based on an engineering modeling method called FEA (finite element analysis) that's so math intensive, analyzing a speaker at multiple power levels takes several hours on a 2.8GHz Pentium 4 computer. The result of this high performance technology is that JL has done an incredible job of using these powerful tools to make a woofer that stays very linear up to the extreme volume levels, and this means lower distortion, higher accuracy and better transients.
Cooling, in addition to the frame vent scheme, is provided by yet another new proprietary pole venting system. The W6v2 has a patent-pending dual-pole venting system. Vent holes are located at the attachment point of the voice coil former and the cone and at the rear of the large pole vent. The exhaust is not the usual open "hole" that you see in most subwoofer motors, but is instead covered by a metal exhaust port device. This device consists of a flat plate that sits about 11/48-inch above the vent in the pole piece and forces air through a series of 15 small vent holes. The metal plate provides a pneumatic loading that forces air to flow in and out of both the top vents near the cone and the rear vent. This innovative pole venting system offers a balanced flow in both directions to maximize cooling efficiency. For increased motor linearity, the pole is extended above the front plate about 5mm.