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View Full Version : 1.82 cuft sealed enough...



cjj2d
04-02-2004, 10:07 AM
for a mag15??

djvi0lent
04-03-2004, 02:42 AM
If thats after displacement, and you added lots of polyfill.. It'd prolly be ok, but I could be wrong.
-Marcus

cjj2d
04-03-2004, 12:25 PM
why add polyfill? SI reccomends 2 cuft sealed. That 1.82 is after displacment.

djvi0lent
04-04-2004, 04:07 PM
I'm pretty sure the 2cubes that SI recommends is after all displacement. The polyfill tricks the driver into thinking it's a larger box. You'd need a little over a pound and a half for your box of 1.82 cubes. I believe the ratio is 1lb polyfill to 1cube of airspace. I'm making a sealed box for my mag15 @ 2.5cubes and most likely won't be adding any polyfill.
-Marcus

djvi0lent
04-04-2004, 04:19 PM
Actually, after a little reading I did, it doesn't make the sub think the box is bigger.. read what Donn had to say on this subject.


its not really that the sub thinks the box is bigger....it changes the acoustical properties of the enclosure.

when you stuff any box full of fiberous material it slows the backwave. in doing so, you create better low-end frequency response. the amount the backwave is slowed is directly proportional to the amount of stuffing used. If your box sounds like crap below 40hz, pack that sucker full. if it gets a little response but not quite enough, just use the suggested 1lb/cuft.

cjj2d
04-04-2004, 06:55 PM
I have a 15D2 as well, why are you going with 2.5 cubes sealed?? I am probably going to build my box closer to the 2 cubes recomended. is there any advantage to going 2.5?

djvi0lent
04-04-2004, 11:51 PM
I'm going a bit larger than recommended to provide a little better low end response.
-Marcus



Advantages of large sealed box over small sealed ...

- Less cone distortion
- Better transient response
- More accurate
- Louder low-frequencies
- Smoother roll-off