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Polyfill in sealed box


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Posted

Once again I'm apologizing just in case there is a search feature here and I'm just not seeing it. I know what it's like to have lazy noobs come to a forum and expect everyone who has paid their dues to just spoon feed them. That sincerely isn't my case.......but I'm going to ask a question that has probably been asked too many times already. Sorry!

Would it be beneficial to put polyfill in a sealed box built to the manufacturer's recommended size? For example, I built a double box with two identical chambers seperated by a baffle resulting in each chamber having an internal volume of exactly 1ft³ each, which is what the woofer manufacturer suggests. Should I just go with that suggestion, or will polyfill have a positive effect? Negative effect? I'm not really anxious to remove the drivers after mounting in a feeble attempt at tuning unless someone credibly tells me that the results could be worth the trouble.

Thanks for reading!

Posted

It can still be useful to put in polyfil to help with standing waves and absorption. It may or may not help your low end, but it should help even out your response. You may try just lining the walls with it, but it is always nice to experiment with it to see how it changes in your listening environment.

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Krakin's Home Dipole Project

http://www.stevemeadedesigns.com/board/topic/186153-krakins-dipole-project-new-reciever-in-rockford-science/#entry2772370

Krakin, are you some sort of mad scientist?

I would have replied earlier, but I was measuring the output of my amp with a yardstick . . .

What you hear is not the air pressure variation in itself

but what has drawn your attention

in the two streams of superimposed air pressure variations at your eardrums

An acoustic event has dimensions of Time, Tone, Loudness and Space

Everyone learns to render the 3-dimensional localization of sound based on the individual shape of their ears,

thus no formula can achieve a definite effect for every listener.

Posted

No benefit to be gained, but i would add the poly batting to reduce standing waves inside the box.

01 Ford focus ZX3

Pioneer AVH-X491BHS

PPI PC 4800.2

Morel Maximo 6.5" x2

Posted

No one could really know what specific results you will have.

Just try it if you are curious it's not like it's expensive or hard to do.

That being said a lot of people's definition of "music" is a clipped 30 hz sine wave with some 80 IQ knuckle head grunting about committing crimes and his genitals.

Posted

Like Krakin said, its a cheap and easy experiment to do. I doubt you will notice much difference though. The frequencies we put to our subwoofers are too low and the boxes are too small for standing wave to be much of an issue.

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

Posted

There is a search button at the top right of the tool bar on the main forum screen. If you're taking displacement of subs in to consideration, the box might be slightly smaller than recommended. With that in mind, it may be to your benefit to add some polyfill. Polyfill will "trick" the subs in to thinking they're in a larger enclosure, and should provide better results. The stuff is dirt cheap, you can even tear up an old pillow to get it. The best way to find out, is to get in there and try it! Best of luck!

2007 Chevy Aveo Ls sedan

2 Sundown Xv2 on scv4k @ .5 ohm

2 pair RE XXX 6.5 components on sax200.4 @ 2 ohm

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Two runs ground from rear bank to chassis

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Singer 220 amp alt

Posted

What poly batting does is to reduce the noise the box makes from resonance from the sub allowing a much deeper and richer sound.

01 Ford focus ZX3

Pioneer AVH-X491BHS

PPI PC 4800.2

Morel Maximo 6.5" x2

Posted

...double tap.

"Nothing prevents people from knowing the truth more than the belief they already know it."
"Making bass is easy, making music is the hard part."

Builds:

U7qkMTL.jpg  LgPgE9w.jpg  Od2G3u1.jpg  xMyLoO1.jpg  9pAlXUK.jpg

Posted

Thanks for the replies! Guess I'll do some experimenting.

Thanks for the pointer hoit! BTW, the subs I'm using are Infinity Kappas and the box volume includes the sub displacement, the way I read it. The owners manual gave very explicit dimensions for sealed and ported boxes. Made it simple so far.

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