mp3wannabe

I am currently building a new fiberglass box for one of my subs (im gonna see how one sounds before building the second box) my question is for the sub i have, the manufacturer recommends 1.25 cubic feet of airspace in a sealed box, but i have also read elsewhere for the same sub that i only need .75 cubic feet...i dont really know what the final volume is going to be for the box, my calculations came out right around 1.0, do i need to stuff the box with poly-fill or something so that i dont blow my sub? or should i try to make the box bigger while i still have some left to do? or is 1.0 or a little less ok, even if the manufacturer says i need 1.25

MisterT

I would try it without the polyfill first. Most manufacturers will be able to help you with whether or not your box is adequate enough for the amount of cubic inches you have to work with. If you do polyfill, be careful. I put too much and it sounded like ****! I then took out enough so that it was 25-50% polyfill and got better performance out of, but with no polyfill in it resulted in the best of the 3.

MiStEr T

mp3wannabe

thanks man, its gonna take me a few more days until i can finish the box anyway, maybe i'll modify my design slightly, and give it a little more room, and then stuff it with pillow stuffing that weve got around the house if i think it needs it.

hihoslva

You should be fine at 1 cube vs. 1.25. Sealed enclosures are very tolerant of varying volumes.

Basically, a larger enclosure will play lower, and with less power. A smaller enclosure will have a harder time hitting the low low stuff, but will take more power safely.

Personally, I prefer to take the middle-of-the-road approach (as you are going to do). A very small enclosure can sometimes restrict cone movement to a point where your output is less than satifactory - not enough bass. At this point, adding power is futile, as you will likely overheat and fry the sub.

I have also never heard any benefits from polyfill. I've used it, and don't know why. All it seemed to do was "deaden" the sound - but chances are your fiberglass enclosure will not be too boomy, and you'll do just fine without it. I'm not using any now in my fiberglass enclosure, and I'm very happy.

~HH

mp3wannabe

thanks a lot HH, you are the reason i am even trying fiberglass to begin with

by the way...thanks for the wonderful tutorial

irish6714

Check this out

I have a friend that builds home stereo systems for real rich people. He also does car stereo (sometimes). If you look at the link about its about a "poly fill" type of stuff. This is the stuff you will want to use. He recomends this stuff. I put some in my box, and the difference was like night and day. Stay away from the white poly crap that is used to stuff dolls and pellows, it does not do much for soud.

hihoslva

And YOU (and those like ya') are the reason I wrote the tutorial in the first place!

Good luck - feel free to let me know if I can be of any help.

~HH

mp3wannabe

well just thought i'd let you guys know that the box is done, no pics yet, my dad's borrowing the digicam...its bumpin, but im still getting used to dropping from 2 12's to 1 for now, until i build another box for the other one
it's not as perfect as i wanted, im a bit of a perfectionist, but the final covering did a good job of covering up blemishes, except that the final color is brown

once again, thanks to HH for the tutorial, without it i never would have even considered trying this myself....

couple of other things that i did, i put some liquid nails into the seams where the back connected to the front, just to seal things up a little better, seems to be more secure now, used a VERY strechy fabric for final covering(had it sitting around, ugly brown color). i used cotton/poly for the molding of the front, but it was too thin and didnt strech enough to cover the front well. i also secured this on using a tacky craft glue instead of the spray adhesive, this stuff worked great.