JL Car Audio Subwoofer - JL18W3

The subject of this month's review, the new JL18W3 18" subwoofer, is certainly no exception. Like all of JL's products, the W3 series is rather feature laden. The 18" W3 subwoofer is built on a heavy custom stamped metal frame with substantial rear excursion distance (47 mm) for the spider provided by both the frame's construction and by a vented spider standoff. The cone assembly consists of a stiff mineral filled polypropylene cone with a 6.5" hard poly convex dustcap (silk-screened with the JL logo), foam surround and cloth type spider. The cone has a unique flat edge for attaching the surround and also adds stiffness to the outside diameter of the cone. The surround is fairly large, about 1.25" wide and 0.75" high, and is intended to accommodate the long excursion capability of the voice coil. The foam used in JLs surrounds is referred to as "double-density" which the company maintains provides superior lateral stability compared to rubber and Santoprene type surrounds. Providing the rest of the compliance is a large 8" diameter flat progressive roll spider ("progressive" refers to the spiders ability to decrease its compliance as excursion increases). The mounting platform for the spider is vented, adding to the airflow across the forward area of the voice coil.

One of the most interesting technical features, besides some neat tricks in the motor system, is JLs patented VRC, a clever mounting platform that provides an improved mechanical joint for the critical glue bond between the cone, spider and voice coil, as mentioned earlier. If your woofer comes apart here, you're out of business. Not only does this high temperature plastic collar provide increased surface area for an improved mechanical joint (as well as strengthening this area so it doesn't lose its shape on long hard excursions), but it also provides vent tunnels that force air across the voice coil for additional cooling. The 18W3 (and the 15" version, the 15W3) uses a modified version of this system called VRC+. This combines the VRC system plus JLs own patented type of peripheral venting. The pole piece on the 18W3 is not only vented down the center, but also has a series of 12 lateral vents positioned just above the vent area. Located in this manner causes the vents to push copious amounts of air into the area of the voice coil that gets the hottest, the top area that rides outside the gap. Taken all together, this driver has four systems designed to increase air flow across the voice coil for increased thermal stability: a vented spider platform; the venting in the VRC; the center pole venting; and the lateral pole venting. This is a very well-conceived thermal system.