Next I measured the T/S parameters. This was done using my usual battery of test equipment from LinearX; the LMS analyzer with Windows 9x software, the new LEAP 5 Enclosure Shop CAD software, and the LinearX VIBox. Once all of the data was collected, the LEAP 5 software was used to generate the T/S parameters and computer box simulation data provided in the Data Chart.
The parameters listed in the Data Chart were used to develop computer box simulations using LinearX's LEAP 5 Enclosure Shop. The JL Audio 12W6v2-D4 was intended for high SPL performance in small sealed or vented boxes but since I personally prefer small sealed enclosures with Qtc's in the range of 0.7, I programmed LEAP 5 to simulate the woofer's operation in two closed boxes, one with a net internal volume of 1.0ft3 and the other with a net internal volume of 1.25ft3. Neither box was simulated with any fill material, such as fiberglass. However, you would be able to get the same box Qtc's in smaller boxes if that technique were employed.
In the 1.0ft3 sealed box, the JL Audio 12W6 v2-D4 produced a low-frequency roll-off of 48.3Hz with a box Qtc of 0.81. The LEAP 5 graph curves shown in Figure 3 (below) depict the SPL at 2.83V (blue curves) in half-space (imagine a woofer mounted flush in a car door that had been removed from your car, and that the door measured about 10 miles by 10 miles: that's half-space), 2.83V in a 154-cubic-foot car compartment (black curves), and the SPL at a power level required to get maximum linear excursion (red curves), also calculated in the half-space measurement domain. To keep them separate, the 1.0ft3 sealed box curves are solid lines and the 1.25ft3 box curves are the dashed curves. Increasing the voltage input to the 1.0ft3 computer simulation to 100V increased the woofer excursion to roughly its point of maximum linearity (above which distortion starts increasing) which is Xmax + 15% and yielded a serious 116.5dB.
The alternate sealed 1.25ft3 box simulation resulted in a lower -3dB frequency of 45.0Hz with the expected lower box Qtc of 0.75. Ancient Chinese wisdom (and solid engineering practice) dictates that the larger the box is for a given woofer, the less voltage it takes to make the woofer over excur. For the 1.25ft3 computer simulation, it required only 90V to reach a maximum linear SPL of 115dB. OK, now for my usual comment about hearing damage and loud music: life goes on for a long time, so don't be stupid with your hearing at a young age and go get that Radio Shack sound level meter for your car so you know how loud the music really is. Trust me, this sub will play louder than this and still sound good.
Like I said in the beginning of this review, the W6v2 may be a step down from the W7, but it's not a huge step. Like the W7, this driver delivers some really outstanding performance numbers. I can generally get some idea of whether a woofer is going to be good musically from all this technical analysis, so I'm guessing up front that Eric thinks this is a pretty hot ticket. So just how does it sound, Eric?
Subjective
I have to agree with you, Vance. The JL Audio 12W6v2 is an impressive subwoofer and the company has an awful lot to be proud of with this product. The original W6 was like catching lightning in a bottle. It broke new ground and created new concepts in applications and thinking. And it looks to me like JL Audio has once again bottled that lightning with the all-new W6v2 series.