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Polyfill?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=40526
Printed Date: May 10, 2025 at 6:05 PM


Topic: Polyfill?

Posted By: Thuan
Subject: Polyfill?
Date Posted: October 08, 2004 at 1:03 PM

I just bought a box for my JLw6 and the guy working there told me to fill it with polyfill or the cotton stuff they sell for pillows...is he right?  How do I know how much I need? Its a 1.4 cu ft enclosure.

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Thuan



Replies:

Posted By: boxmaker85
Date Posted: October 08, 2004 at 1:07 PM

is the box build to exact (or close to) JL specifications?  If so then just use some to help stop a standing wave inside the box.  If it's smaller (not that much smaller b/c polyfill doesn't do THAT much) then you could lightly stuff the box with it.  Polyfill lets the sub "think" that it's in a larger box than it really is b/c it slows down the sound wave.  BTW what size is the sub b/c the w6 are small box subs.  1.4 is big for one of those isn't it?





Posted By: Wiseguy
Date Posted: October 08, 2004 at 1:10 PM
https://www.the12volt.com/installbay/forum_posts.asp?tid=22330&KW=polyfill

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Posted By: Thuan
Date Posted: October 08, 2004 at 1:13 PM
JL recommends .90 - 1.50 cu ft enclosures. I posted about this and people were telling me to go with 1.25 and someone told me that I should account for actual net space after the sub is installed. So the box is 1.4 but Im not actually getting 1.4 because the magnet and frame takes up some of that...am I on the right track or should I return the box?

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Thuan




Posted By: DYohn
Date Posted: October 08, 2004 at 1:14 PM
Polyfill will change an enclosure's performance such that there is an increase in apparent enclosure size by as much as 40%.  For subwoofers, standing waves inside the enclosure are not really a problem.  The rule of thumb I use is 1lb per 1cuft of enclosure space.  At that fill rate, standard dacron polyester batting that you can buy at fabric stores will change the enclosure's performance as if it was about 20% larger, and high-performance polyfill such as Parts Express' "Acoustastuff" will change the performance to about 30% larger.  Make sure the polyfill is not up against the speaker's magnet structure, as the heat generated by the speaker can cause it to burn, and make sure it is not blocking your ports (if any.)  Ignore anyone who tells you to use fiberglass house insulation, as this stuff can damage your speakers.

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Posted By: Thuan
Date Posted: October 08, 2004 at 1:23 PM
So its actually better to have the subwoofer think that its in a larger enclosure then it actually is in? 1.25 cu ft is what other recommended me but I went with 1.40 because the magnet takes up some of this space....is it recommended that I add polyfill to this? Should I find a way to attach the polyfill to the insides of the box or just "throw" it in there?

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Thuan




Posted By: DYohn
Date Posted: October 08, 2004 at 2:02 PM
I suggest adding 1lb of polyfill to your enclosure.  Mount your speaker and try it.  If it's too boomy, you have too much polyfill, remove the speaker and pull some out.  If it's too punchy or ":tight" sounding, add some more.

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Posted By: Thuan
Date Posted: October 09, 2004 at 4:13 AM

k, thanks....ill try that.



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Thuan




Posted By: jeffchilcott
Date Posted: October 09, 2004 at 3:30 PM
the best street beat box that we build for the w6v2 series subs is 1.38 cu ft internal with a vent tuning of 38 hz...this is a great box and will produce low to mid 140's with 10 inch w6v2's with the power they take and then a little more

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2009 0-1000 Trunk WR 154.0DB 2009 1001+ Trunk WR
2007 USACI World Champion
2007 World Record
2006 USACI Finals 2nd Place





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