I am in the process of constructing the enclosure in the photo below for the area behind the seat of my truck. I will be installing a JL Audio 10W3V3. In trying to keep things mounted as low as possible, I am extending it along the bottom of the cab to make the reccomended amount of air space. Does anyone see a problem with this irregular shape? The back of the speaker will be no closer than 1" to any part of the enclosure (except the rear of the magnet, but there is not vent at the rear of this speaker). Should it "see" the airspace without any issues? Any thoughts would be appreciated. Dimension are roughly 11" x 6" inches where the driver is mounted, the extension is approx 5" x 6". Thanks.

It will be fine. A subwoofer doesn't need any particular ratio in the enclosure...just the right amount of air space. Make sure no part of the woofer comes in contact with anything at full excursion.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
yeah thats a pretty kick ass enclosure. i would make sure it is properly braced inside that while its still open. cause even though it wont be a big SPL system. it still wouldnt hurt.
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99 Blazer LT. Yellow Top. Big 3. Infinity Kappa Speakers All Around. Jensen CD/DVD flip out. 2 Infinity Kappa Perfect 12DVQs powered by a Alpine PDX600.1 (in one custom box, building a FG box)