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Awesome. I knew venting wouldn't be an issue, the 1/8" gap was too make sure the magnet doesn't touch/rattle on the back of the box. What I was worried about is if it'd be a week point only leaving the wood 5/16" back there. I'm not planning to poly-fil. Thank you, I'll finish assembly as is.
Apparently geometry isn't my strong suit, I thought I'd have enough room to recess the woofer but it didn't work as planned. It is a 0.8 cu ft sealed enclosure for a single Sundown SD-4 10 D2. After using the router to cut a half moon, I have as little as 5/16" left with a 1/8" gap between the magnet and wood. I'm not sure if the thin layer of titebond will help but I put it there hoping the semi rough area will absorb some. The box is built with 3/4" MDF, if it were for me I'd try it with the cut and if it failed I'd rebuild it but that's not the case. The person this is for isn't a bass head, he listens to things like Peter Frampton. It's not a customer, he's just a friend but I don't want to send him off with something that'll fail. The amp he's using is a Kicker Key 500.1 and I doubt he'll really crank it. Even if he did, I'm not sure the amp can push it to its full potential anyway. It's a 600W RMS sub being powered by a 500W mini amp. I know I can cut a hole and place another piece behind it but I built this to angle with his backseat. Doing that will make the box stick out that much further which I'm hoping to only do if I have to. I know that's the best way to do it, but is it essential? I appreciate any input, I'm hoping this will work but I'm wanting to run it by you guys first.