I know a lot of companies and a lot of engineers in the car audio "game" and I would have to say that JL Audio is certainly on the short list of the manufacturers I consider to be serious professionals at what they do.
This company has been specializing in car audio products since 1975 (national distribution of JL's subwoofers began in 1992), and it goes without saying that JL Audio has long been considered a major player in the subwoofer marathon that we have been witnessing for the past years. Known for their innovative engineering approach to speaker design, JL Audio has produced some very real improvements in subwoofer technology. They were among the earliest companies to use layered voice coil windings beyond four layers, and their patented vented reinforcement collar (VRC) that greatly strengthens the critical bond between the voice coil former, spider and cone was also a smart idea for its time. Not to rest on past glory, JL has recently released a W7 subwoofer series is perhaps even more innovative than any of their previous products. Which brings us to the subject of this review, the JL Audio 10W7-3.
Besides answering the body of questions I give to every driver manufacturer when they submit a product for review, I also got a technical "white paper" type of document from JL Audio that does a very nice job of describing the W7 technologies and the methods employed to design this woofer group. If you are interested in woofer "science", get a copy of this as it has some interesting insights into the inner game of woofer design. The paper begins by acknowledging the limitations of Thiele/Small simulations, correctly stating that this is a small signal representation and does not at all describe the dynamic functioning at higher power levels where listening is really done. While the T/S simulations are still a reasonable guide for developing enclosures, making a woofer that also sounds good at high volume levels goes way beyond this paradigm. If you ever wondered why woofers with identical T/S parameters can sound so very different, it's just that there is a lot more to understand about woofers than is described by this methodology (incidentally, JL Audio sort of unfairly lumped LinearX's LEAP into the category of box design software that does not take into account dynamic non-linear behavior. Even in its old DOS LEAP 4.6 incarnation, LEAP had both non-linear compliance and non-linear Bl models built into the analysis as well as dynamic voice coil temperature computation. However, the new Windows version that's soon-to-be released goes substantially further in the direction of non-linear analysis).