The larger 1ft3 box simulation had a lower 3dB down frequency of 47.0Hz with a lower box Qtc of 0.69. However, as is always the case, the larger the box the further the driver has to move, so it takes less voltage to achieve the Xmax +15 percent linear excursion maximum. The computer simulation required only 44V to reach a max linear SPL of 115dB, still loud enough to leave you deaf at age 60 if you rock hard for 30 years. Since these numbers are based on steady state (sine wave) analysis, the performance with program material will be at least 2-3dB greater before noticeable distortion. You should also keep in mind that low-frequency distortion is very hard for the human ear to detect. Distortion percentages as high as 15 percent generally are not really detectable except with measuring equipment. At high frequencies where your midrange and tweeters are working, it's an entirely different story.
Kenwood has a reputation for building quality audio products and the new Excelon woofers are good examples of this. While the KFC-XW1300DVC probably won't be a big hit with the dB Drag crowd, it's got more than enough muscle to do the job for the rest of us. While the type of analysis you just read about describes the technical aspects of a woofer's performance, it really doesn't address the actual subjective sound quality. For that, we ask Eric. -V.D.
Subjective
Well Vance, the new Kenwood KFC-XW1300DVC is an oddity in a sea of new oddities that are becoming the common place in design and function. Kenwood has gone out of its way to create an odd subwoofer. Much like JL Audio, Kenwood has gone the route of odd size 13" sub, not the standard 12" or a 15". The KFC-XW1300DVC is also a very tall subwoofer with a height of 10 3/5 inches, giving an almost square appearance to it out of the enclosure. It even has a different looking cone that is made of a woven PBO fiber and features an embossed tornado shape.
Kenwood has invested a ton of money in the tooling to produce this subwoofer and the technology to design it. It's a big subwoofer, a real hulk. As I have written about in past articles, it seems that the new rave in subwoofer design is big in all phases of design.
Installation
I got a hold of Rick Noetzli, Kenwood's Director of Training, to get some insight into this fascinating subwoofer and to get the company's official enclosure recommendation for maximum sound quality. I asked Rick why a 13-in over a conventional size. His answer was a bit anti-climatic. I was hoping for some breakthrough in geometric design or some computer modeling FEA superiority or at the very least a bunch of marketing mumbo-jumbo to mull over and have fun with, but no, Rick said it was for the more conventional and frankly more truthful reason that a 13-in is bigger than a 12-in and thus should be able to move more air. Logical.
Rick recommended a sealed enclosure of 1.81 ft3. This is a gross enclosure volume, and not a net volume like most other manufacturers would give you. This means that I would not have to add the KFC-XM1300DVC's hefty displacement of 0.45 into it and that the enclosure was therefore a net volume of only 1.36 ft3. (By the way, the Kenwood KFC-XW1300DVC is now the record holder for the largest displacement of any subwoofer so far.)
I had my guys at Speaker Works build an enclosure of 1.81 ft3 and installed the KFC-XW1300DVC into it. Out to my Scorched-Earth Black Ford F-350 Super-Duty-Dually-Crew-Cab-Diesel truck to finish up the installation and set-up the listening test.