Hasdrubal
Senior Member
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- Nick
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- Dec 27, 2020
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- Puyallup WA
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Anyone who's seen my posts here knows I'm not an audio expert, but I'm willing to experiment. Yesterday I finished a sub box for the trunk, and figured it might give people some ideas. It's not perfect by any means, and I've already thought of some things to improve. The photos might show that I'm not the best at fiberglass layup.
Box has a 1/2" plywood face, mostly because that's what I had around. I know MDF is pretty standard for enclosures, but I'm not buying a whole sheet of the stuff for an experiment. Body is fiberglass, 2-3 layers depending on how I had to cut around curves. Don't remember the fabric weight, it's probably about 8-9oz.
Started by shaping a foam plug for the right corner of the trunk, not an exact process. Basically just took a block of foam and sanded until it seemed like a good fit. Traced the plug face onto the plywood, then sealed it with a few layers of paint.
Anyone who's done structural fiberglass knows the proper way is to make a female mold off the form, and then use the mold to make your part, so it's dimensionally accurate. I didn't do that here, mostly because the box doesn't need to be dimensionally accurate, and I wasn't going to make multiple parts to need a mold. Also, I didn't want to spend twice as much time in case it didn't perform.
I had bought a Polk 8" dual coil sub, because I thought it would fit in the factory location, and I have an amp that won't bridge channels but will link two for identical signal. The sub wasn't even close to fitting, but just like the plywood, I didn't want to get something new for an experiment. There's probably better subs out there, but this is what I have for now.
All that being said, it sounds pretty good. Anything is better than the factory sub, I think, but I'm not disappointed. Not terribly loud, but my amp is only running 80w RMS to it, so not a big surprise there. I should have planned this all better, but I don't want to add another amp, and the one I chose was based on poor understanding of the stock system.
If I went to do this again, I'd use more layers of fiberglass. This ended up being about 1/8" thick where the corners caused the fabric to bunch up, and a bit thinner on the rear face where it's flat. The rear face flexes noticeably, which I think is considered bad. I'd also choose a sub based on its specs, like more sensitivity to account for the lack of power- would be cheaper than replacing my amp, anyway.
I still need to get some industrial velcro or something to secure the box, and rerun the wires after getting my spare tire kit situated.
The sub that's in there is this-
https://www.crutchfield.com/p_107DB842D/Polk-Audio-DB-842-DVC.html
Was thinking about swapping for this, since I'm not limited on size-
https://www.crutchfield.com/p_575R2D210/Rockford-Fosgate-R2D2-10.html?tp=111
Box has a 1/2" plywood face, mostly because that's what I had around. I know MDF is pretty standard for enclosures, but I'm not buying a whole sheet of the stuff for an experiment. Body is fiberglass, 2-3 layers depending on how I had to cut around curves. Don't remember the fabric weight, it's probably about 8-9oz.
Started by shaping a foam plug for the right corner of the trunk, not an exact process. Basically just took a block of foam and sanded until it seemed like a good fit. Traced the plug face onto the plywood, then sealed it with a few layers of paint.
Anyone who's done structural fiberglass knows the proper way is to make a female mold off the form, and then use the mold to make your part, so it's dimensionally accurate. I didn't do that here, mostly because the box doesn't need to be dimensionally accurate, and I wasn't going to make multiple parts to need a mold. Also, I didn't want to spend twice as much time in case it didn't perform.
I had bought a Polk 8" dual coil sub, because I thought it would fit in the factory location, and I have an amp that won't bridge channels but will link two for identical signal. The sub wasn't even close to fitting, but just like the plywood, I didn't want to get something new for an experiment. There's probably better subs out there, but this is what I have for now.
All that being said, it sounds pretty good. Anything is better than the factory sub, I think, but I'm not disappointed. Not terribly loud, but my amp is only running 80w RMS to it, so not a big surprise there. I should have planned this all better, but I don't want to add another amp, and the one I chose was based on poor understanding of the stock system.
If I went to do this again, I'd use more layers of fiberglass. This ended up being about 1/8" thick where the corners caused the fabric to bunch up, and a bit thinner on the rear face where it's flat. The rear face flexes noticeably, which I think is considered bad. I'd also choose a sub based on its specs, like more sensitivity to account for the lack of power- would be cheaper than replacing my amp, anyway.
I still need to get some industrial velcro or something to secure the box, and rerun the wires after getting my spare tire kit situated.
The sub that's in there is this-
https://www.crutchfield.com/p_107DB842D/Polk-Audio-DB-842-DVC.html
Was thinking about swapping for this, since I'm not limited on size-
https://www.crutchfield.com/p_575R2D210/Rockford-Fosgate-R2D2-10.html?tp=111
