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Discussion Starter #1
Hey guys, need some help here. I have a 2011 Tundra that came with come crappy 12 speaker JBL system. I replaced all my speakers with Dayton's and took out the stock sub and replaced it with a Kenwood KFC-XW800F slim 8". I installed a JL E1200 120wRMSx1 amp for it.

I used the stock JBL box as I wanted to make this as stealth an install as possible. My issue is that after the break in period the sub is sounding a little boomy and seems like if I turn it up at all it hits xmax I think, Sounds raspy almost. I checked and there are no leaks and its a sealed box. Its ABS plastic, and I covered it in 80 mil dynamat just cause I had some extra laying around.

I've filled the box with some poly fill, but I just looked over the specs and the speaker says the recommended sealed size is .5 CU FT, I think my box might be too large. Here's a pic, getting an exact measurement will be hard as the box has all sorts of indentations and protrusions to fit perfectly where it does.

How should I go about tunning this? Should I add something to the inside of the box to try to cut down on size and see if that helps? Should I stuff the crap out of it with poly fill? I'm not new to the electronic side of this, but box building is a new foray for me, and help is awesomely appreciated!

Can't post pics till 5 posts....so they are coming :(

 

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How deep is that thing? I would either try to make a good estimate of the box volume so someone could model it for you or just keep trying different amounts of poly to see what sounds better.
Nice to see some TT members
 

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Discussion Starter #4
I'll try to take some measurements tonight and see if I can get a rough estimate. I'll try jamming that mother full of poly as well and see where that takes me.

TT FTW :)
 

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The easiest way to determine enclosure volume, if it is impossible to measure, is to fill it with a medium. I like to use cat litter or rice.
 

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The box is plastic, you can fill with water also, just make sure its dry before reinstall. Use wood blocks or high density foam to remove volume....or better yet ditch the OEM box and build one for the driver. The plastic box is flimsy as poop and will not sound as good as a real box.

Good luck

~JH
 

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Discussion Starter #7
So I measured it out, it wasnt as big as I thought. About .86 cubic ft. There's definitely some error in there. Displacement is about .031 + error so let's say its .75 cubic ft. If I overstuff polyfill, almost 3lbs per ft. I can lost 15-20% of my cubic space per Sub Box Polyester Fiberfill

So 17% off .75 is about .623 cubic ft.

Ideal size per kenwood is .5 cu. ft.

I think I'm actually about dead-on on the size as there are indentations and cut outs that I didnt take into account for simplicity. I didnt want to remove the box, so the rough estimate should do for now.

Initial sound check...and SWEET! It definitely sounds better, deeper, more response down low where it counts. Night and day difference. So glad I randomly thought about this today lol. I'll let you know how it goes over the next day or so. Can't crank my stereo too much tonight.

Thanks guys! I was thinking about getting rid of the box and making my own with 2 of these 8"s. Although I'm not sure I can now if the box is only .75 or so cu ft. I would need 1 cu ft for two. Hmmmm...
 
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