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View Full Version : Polyfill in a 3 cu.ft ported box



vario
03-26-2008, 09:28 PM
I have a 3 cubic foot box with a 6 inch pvc port. How much polyfill should I put in?

iDesignBoxes
03-26-2008, 10:00 PM
I have a 3 cubic foot box with a 6 inch pvc port. How much polyfill should I put in?

http://www.soundsolutionsaudio.com/forum/index.php?showtopic=7168&mode=threaded

vario
03-27-2008, 01:33 AM
will it reduce port noise? certain songs, especially pink floyd's on the run cause the port to fart

Immacomputer
03-27-2008, 11:11 AM
will it reduce port noise? certain songs, especially pink floyd's on the run cause the port to fart

No. Polyfil is not what you need. You need more port area or a flared fort. I would suggest either using 1 flared (aero) 6" port or use about 4 4" PVC ports. Make sure to recalculate the length that is needed for your tuning.

Oh and the reason that song causes port noise is because it is very close to your tuning. That song has some 32hz material in it that will really cause the port to oscillate and so you will get port noise if you don't have enough port area.

vario
03-27-2008, 08:48 PM
No. Polyfil is not what you need. You need more port area or a flared fort. I would suggest either using 1 flared (aero) 6" port or use about 4 4" PVC ports. Make sure to recalculate the length that is needed for your tuning.

Oh and the reason that song causes port noise is because it is very close to your tuning. That song has some 32hz material in it that will really cause the port to oscillate and so you will get port noise if you don't have enough port area.

Thanks I really appreciate it. I expected the 32hz waves in that song to cause that but its good to have it clarified as I'm not much of an engineer.

I take it the inside edge should flare outward? Is there an easy way to do that with a home made pvc arrangement? I have a heatgun so it may be possible to heat it and then flex it out, but if its possible to buy something from home depot it would be preferred.


Also, would polyfill result in any greater sound quality?

dB-SPL
03-27-2008, 09:14 PM
Polyfil is generally used in boxes that are small in volume. It 'tricks' the driver into thinking that it's in a bigger enclosure than it really is. So whether Polyfil will help your SQ or not depends on your box volume, tuning and what driver you're using.

-Bill-

vario
03-27-2008, 10:37 PM
I put in 30 oz. Im not sure that the drivers are doing as much excursion as before, the trunk is rattling less, overall it sounds slightly better but not as loud (I think, either that or im getting deaf which is a possibility)

Immacomputer
03-28-2008, 01:19 AM
If you put too much in a ported enclosure, you almost defeat the purpose of a ported box. Too much and the port won't function and you basically have a large sealed enclosure. If you're going to put polyfil in a ported enclosure, only line the edges with it and keep the center area open.

Like I said before, polyfil is not your answer. You could use the heatgun to create a flare but you need to find some glass type veil to use as a base that won't melt. It can be done but the trick is finding the right base.