I have a JL 10w3v3 sub. The problem is that the enclosure i'm using for it is a formerly 8'' enclosure custom made for my 2001 sentra. The installer told me that i could use this encosure if we made it a 10'' which we did. Now i'm afraid the box is too small. After doing a research i've found that if the enclosure is too small the sound could be affected and so does the sub.(right now the sound is pretty decent but sometimes it lacks presence) JL recommends a .625 enclosure (sealed). Should i get a .625 box? how important is that my box is exactly the size JL recommends? Is poly-fil an option? thank you. i could send a picture if it helps.
I don't know how small your box is, but the volume of the box plays a critical role in how your sub will perform. The larger the box becomes, the deeper the sub will be able to play. The downside is the bigger the box is, the less power the sub can handle. JL recommends a .625 box size as a compromise between deep bass extension and high power handling. You can go larger (which i usually prefer) or smaller than they recommend. Your sub will surely work in a smaller box, but if the box isn't large enough you may find you get deeper bass with an 8". Poly-fil can make some difference. It adds mass to the air inside the box, making the sub sound as if it were in a larger enclosure. Figure about a 10% increase in box volume when filling it with Poly-fil. A box that is .5 cubic ft would act as if it were .55 ft. That's not a big difference, but it does help.
Thanks for the information it was very helpful. I measure the box and this is what i got:
d 8.5" bottom 5'' top
w 11.5 wider part (middle) 6.5 shorter parts (top-bottom)
h 13"
is this enough? Am i close to .625 cu feet?
if you give me an email adress i could send you a photo
Pictures always help. If you upload to an on-line photo sharing site, you can link the image onto the forum. I'm having a little trouble imagining what your box looks like, but i'm calculating an airspace of less than .25 ft, assuming you gave external dimensions and your wood is 3/4" thick. That wouldn't sound great. If you want the smallest box possible, i'd recommend making one with 3/4" MDF with external dimensions of 12"x12"x12" (a 1ft cube). That would be precisely the size JL suggests.
here are the photos. i hope you can see them. I forgot to tell you that the box is plastic ( plastic is thin). It's a factory box that came with the car when bought from the dealer.
*i checked on the box and it has has poly-fil already. (i thought it didnt have). Thanks your attention
If the enclosure walls had no thickness, according to your measurements it's still quite a tight space- .4 cubic ft by my reckoning -
It can be a daunting task to measure the air space in such an awkward enclosure, but the way that works for me is pretty elegant in its simplicity. Get yourself a 1 liter pitcher, the kind available at any discount store for a couple bucks. Get a big bag of packing peanuts. See how many pitchers of peanuts it takes to fill the box completely, and divide that number by 28(a cubic foot is about 28 liters). Easy as pi. I've seen ppl suggest using water, but it seems like too much aggravation to me. Water gets heavy pretty fast.
Sounds like a good idea. Since mine is plastic water sounds like a good option or (what about any kind of matter/objects that doesn't damage the box like for example sand, rice, marbles) Will they do the job.?
I did the math and i'm supposed to fill at least 18 1 liter pitches into the box to approximately match the recommendation of .625 cu feet. Am i right?
18 / 28= .642 Do you recommend more or less?
I will do it and write to you again to let you know the results. Thank you so much J Ro
I suppose marbles and sand can work, but that's a whole lot of marbles! It would be extremely heavy after a few pitchers, so i like the peanuts. I typically use this method to measure fiberglass boxes, and peanuts are so light i don't have to worry about damaging the box. Plus they clean up pretty easy. JL actually recommends .67 for an enclosure when you add the subs displacement, so 18 liters is very close.
As an aside, I've found it helpful to spray enclosures like yours (inside and out, if possible) with a good rubberized undercoating like 3M DynaPro.
finally i measure my box. The results not good: about .307 cu feet. i guess i have to find me another box. right?
yes and no. if you want to use your sub to its full potintal you will want to find a box with the dimentions that JL recomends. for the no part you can continue to use that box but your sound will suffer horrably.
With the correct box i do belive that you will be really impressed with the sub. Right now you are accepting sub par preformance.
If you have some friends that are half way handy with wood you could butter them up and get them to help you build a box, one website that i know of has a cool Box Wizard that will let you play around with some numbers to get the size that you want then give you a picture to go by.
Thanks man! I'm interested in the website. Could you give me the name?
http://www.rockfordfosgate.com/rftech/box_wizard.asp see what you think
I found a box (haven't buy it yet) that measures .776 cu feet. Jl recommends .625 cu feet. Is this box too big?. Should i find another one that gets closer to JL recommendation?