how much air is too much???

[lil' jon]

okay so i started making a fiberglass sub box for my car a few weeks ago. It will hold two 10" Alpine's that require between .75 and 1.25 cubic feet of air. When i initially designed the box it came out to 2 cubic feet or 1 cubic feet per sub which i thought was perfect. Now that I've actually made the box it's kind of grown out of the trunk well and now holds 2.8 cubic feet of air (1.4 cubic feet per sub). Is this bad? I tried to make TWO dividers going through the center of the box to section out the .8 cubic feet but that ended up being a lot harder than i planned. Also...I filled the box up with water yesterday and it has a leak :[. It is however a small leak. Should I fix this? How exactly do I mix that bondo/fiberglass resin mixture that you guys have been using to seal the box?

[Bonemaro]

Re: how much air is too much???

First, yes fix the leak. A seal box needs to be sealed.

Second, at some point if the enclosure get too big, you'll get into a infinite baffle situation, which the sub may or may not "like." At what point is this? Hard to say, depends of the driver. I'm guessing here, but I don't think 1.4 will be horribly bad. It'll probably hit a bit deeper.

[ssms5411]

Re: how much air is too much???

You could always fill the box up with pieces of wood fiberglassed in there to take up more air space. Until you reach your desired amount of air space you need. I think it's funny most people have problems tring to get air space when putting in subs and you hav e too much. Shouldn't be a problem getting to your desired air space level. Good luck.

[lil' jon]

Re: how much air is too much???

i think i'll use your idea of fiberglassing over blocks of wood to take up space. actually, i'll fiberglass over blocks of styrofoam so i don't add much weight. weight was my main concern with this box (i've got a 3.4l v6, afterall) which is why i chose fiberglass. the box only weighs 15-20lbs (without speakers). i wish i could find my digital camera so i could get some pics up. i'm proud of my work haha

[ssms5411]

Re: how much air is too much???

i think i'll use your idea of fiberglassing over blocks of wood to take up space. actually, i'll fiberglass over blocks of styrofoam so i don't add much weight. weight was my main concern with this box (i've got a 3.4l v6, afterall) which is why i chose fiberglass. the box only weighs 15-20lbs (without speakers). i wish i could find my digital camera so i could get some pics up. i'm proud of my work haha

Fiberglassing over the foam is a great idea for saving the weight. Def. try to get some pics when your done. I was going to do a fiberglassing stealth enclosure but back out and bought a subthumb box.

[lil' jon]

Re: how much air is too much???

well today i was able to fiberglass two walls through the center of the box to section out .3 cubic feet of air and seperate the two subs. now each subs has about 1.25 cubic feet of air (that's not bad, right?). Now i'm starting to have second thoughts on the subs i'm using. I was originally going go with the two Alpine Type-E subs and an Alpine MRP-M450 monoblock amplifier. The only thing is the amp is 2 ohm stable and the subs are 4 ohms each. They are not DVC. Would I still be able to wire them up for a total load of 2 ohm? Anyone have suggestions on what subs/amp combo I should use??

[96firebird311]

Re: how much air is too much???

Second, at some point if the enclosure get too big, you'll get into a infinite baffle situation, which the sub may or may not "like." At what point is this? Hard to say, depends of the driver. I'm guessing here, but I don't think 1.4 will be horribly bad. It'll probably hit a bit deeper.

This is true however, it is NO WHERE NEAR 1.4cuft. The increased air space will yield better low frequency extension and a slight increase in sensitivity.

And try to swing a pair of Type-Rs. Check Ebay for some sweet deals.

[lil' jon]

Re: how much air is too much???

alright after some more measuring i've come to the realization that each sub has almost exactly 1 cubic foot of air. i went ahead and ordered the aformentioned sub/amp combo. i bondo'ed the top of the box and sanded it down with 400 grit paper. It's almostttt smooth enough for paint but now i can't decide wether to paint it or carpet it haha. either painting it black with the red chevy symbol in the middle, green with the gold chevy symbol in the middle, or carpeting it charcoal with the red chevy symbol. please help me decide haha.

[tkoforpresident]

Re: how much air is too much???

how bout black with the red PONTIAC symbol =)

pontiac ftw