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View Full Version : polyfil + ported box.... help



maldecido33
06-11-2006, 09:21 PM
I've got a box right now (a custom built truck box) for two 10"s that's sitting at .95 cubes per sub after sub and port displacement. I need to get this number up a little closer to 1.3-1.5 cubes, and the only way I can think to do this is by using polyfil, as I have the dimensions as big as they'll go. Now, since this is a ported box, I need to know **** near the exact Vb of the box in order to properly tune it.

My question is, how do I know how much exactly polyfil will add to my box; or, more specifically, how much polyfil to add to gain half a cubic foot of volume.

Or, any other alternatives to making the box bigger? The ports are already partially external.

86yota
06-11-2006, 09:48 PM
If you add polyfill, isnt it going to fly out of the port?

justinschmiidt
06-11-2006, 09:51 PM
If you add polyfill, isnt it going to fly out of the port?


chicken wire FTW

86yota
06-11-2006, 09:53 PM
ahhhhh Good thinkin.

maldecido33
06-11-2006, 10:08 PM
or stapled down inside the box


any help??

dkc62
06-11-2006, 10:19 PM
I thought adding polyfill makes the box smaller.

maldecido33
06-11-2006, 10:22 PM
it makes the sub "think" the box is larger

Shyne151
06-11-2006, 10:26 PM
I thought adding polyfill makes the box smaller.



it makes the sub "think" the box is smaller

Wrong... and wrong... It makes the sub "think" the box is bigger, not much... but some.

*EDIT*Edited your post I see.

CntInjaDisNinja
06-11-2006, 10:54 PM
All polyfill does is slow down the backwave coming off the subwoofer, so it takes longer for the soundwave too come back and hit the back of the cone, so the sub "acts" like it is a larger box

I heard something, it may not be right but 16 ounces of polyfill= 1 cubic foot

dkc62
06-11-2006, 10:59 PM
Wrong... and wrong... It makes the sub "think" the box is bigger, not much... but some.

*EDIT*Edited your post I see.
Clean out your pm box

Volenti
06-11-2006, 11:10 PM
Any (small) gain you get from the "bigger box" effect of fill will be more then negated by the damping effect of said fill, you'll actually loose peak output by at least 3db.

If the box sounds boomy and you want better SQ then adding some fill is a suitable approach.

If you want more output you can strike fill off the list now.

Shyne151
06-11-2006, 11:44 PM
Clean out your pm box

Cleared.