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polyfill in a ported box?

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=114260
Printed Date: July 06, 2025 at 10:56 AM


Topic: polyfill in a ported box?

Posted By: thatfloorguy
Subject: polyfill in a ported box?
Date Posted: June 05, 2009 at 9:09 PM

Ok I built a 4.75 ft^3 net 65 sq in port tuned to 33 hz as advised by Aznboi. kicker 15L74 wired to 2 ohms, kicker 08zx750.1, big 3 upgrade entire back half of car dynamatted. It slams so hard it hurts. The gain is in between the 1st and 2nd mark on the amp. I am thinking it may be port noise possibly. Will adding polyfill smooth it out or not? Pioneer deh 4900ib HU. I have the bass boost on HU @3 and subwoofer setting @ -10.  I would also like some advice on some decent SQ speakers .(kicker 08zx350.4) 



Replies:

Posted By: djrankin004
Date Posted: June 06, 2009 at 12:57 AM
make a mess if not done correctly




Posted By: aznboi3644
Date Posted: June 06, 2009 at 3:04 AM
you telling us where the gain is means nothing without knowing the input.

The gain is not a volume knob. An amp can put out full power with the gain on the lowest setting or the highest...doesn't matter.

Also make sure all seams are completely sealed...a leak in an enclosure can make a big difference. I doubt it is port noise as there is plenty of area.

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Custom Enclosure Design




Posted By: thatfloorguy
Date Posted: June 06, 2009 at 7:44 AM
I put the top on last when assembling the enclosure, so that i could silicone the joints easier, even around the port. with the 4 1/4 inch opening and the sub cutout I was able to silicone the top panel also fairly easily. I turned the gain down completely and just turned up sub volume on the HU. I am assuming since I built an enclosure for spl and no sq that is probably as smooth as a response as I will get. It seemed to help.Thanks again for the thread Aznboi. You can feel the air move outside the car. I didn't really want to try and remove the enclosure to polyfill it anyway. I had to remove the back/drivers seat plus trim some sheet metal back after pulling the interior plastic panels just to get it in. I only have 6 inches from the port to the trunk lid and the enclosure is up against the rear seat. Is that adequate port clearance?




Posted By: tommy...
Date Posted: June 06, 2009 at 8:16 AM
What kind of noise is it...?

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M.E.C.P & First-Class
Go slow and drink lots of water...Procrastinators' Unite...Tomorrow!




Posted By: thatfloorguy
Date Posted: June 06, 2009 at 2:41 PM
I also didn't take into consideration how stiff the sub is straight outta the box into the enclosure. maybe 30 mins play time so far. plus I was used to the sound of the two cvr 12's before. There is a big difference in the output. It is not really a noise just not as smooth of a response as I expected. I have been tweaking the HU settings with the  amp's gain set to lowest setting, It is coming along. I was just curious if the polyfill would smooth it out some or is that not a good idea in the ported enclosure,( I thought to remove the sub and usea fabric mesh of some sort to keep it from entering the port),  or should I wait until the sub has more play time?




Posted By: thatfloorguy
Date Posted: June 06, 2009 at 2:44 PM
As far as the input I am not sure The cap readout says 14.10 drops to 13.5 on hard low notes. I don't know how to test the system to see the accurate voltage or amperage I am really getting.Would autozone be able to tell me my Alt. output?




Posted By: thatfloorguy
Date Posted: June 06, 2009 at 2:50 PM
I am hoping I constructed the enclosure correctly  the internal volume is 30x16 1/4x24 port is 4.25x16.25x27 1/8  I allowed .4ft^3 for sub displacement and four 2"x3.4" braces 16 1/4 tall I came up with just under 6.35 gross before any displacements.




Posted By: thatfloorguy
Date Posted: June 06, 2009 at 2:51 PM
tha is supposed to be 3/4" on the braces not 3.4"




Posted By: thatfloorguy
Date Posted: June 06, 2009 at 9:07 PM
If there is a leak will a 2nd silicone on all joints and overlapping panels of dynamat  on the interior panels help or will that change the internal volume too much?  Or do I have to rebuild the enclosure since the glue is set?




Posted By: aznboi3644
Date Posted: June 06, 2009 at 10:21 PM
this enclosure is not for SPL.


It is for daily listening.

and dynamat???

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Custom Enclosure Design




Posted By: stevdart
Date Posted: June 08, 2009 at 7:18 AM

"The gain is in between the 1st and 2nd mark on the amp.

I have been tweaking the HU settings with the  amp's gain set to lowest setting, It is coming along."

You've made a couple references to fiddling with the gain, in a manner which indicates that you are not sure of how to set it.  Get that basic task done correctlly before anything else so you can eliminate it from consideration.

For original question, "Polyfill in a ported box?":  I've done it many times.  Used as a liner by spraying glue and sticking it in small chunks.  You don't want any loose polyfil in there.



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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.





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