polyfil + ported box.... help

[maldecido33 10+ year member]

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.

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[86yota 10+ year member]

If you add polyfill, isnt it going to fly out of the port?

 

[justinschmiidt 10+ year member]

If you add polyfill, isnt it going to fly out of the port?

chicken wire FTW

 

[86yota 10+ year member]

ahhhhh Good thinkin.

 

[maldecido33 10+ year member]

or stapled down inside the box

any help??

 

[dkc62 10+ year member]

I thought adding polyfill makes the box smaller.

 

[maldecido33 10+ year member]

it makes the sub "think" the box is larger

 

[Shyne151 10+ year member]

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 10+ year member]

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 10+ year member]

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 10+ year member]

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 10+ year member]

Clean out your pm box

Cleared.