# How important is cu. ft. in a sub enclosure?



## BriIiance (Nov 16, 2011)

I found 3 10" sealed subwoofer boxes, I don't know which to go with. my subwoofer is the vibe audio ba-10, and has a 1 cu ft min and 1.5 cu ft max. I'm not sure what more cu. ft. means but I'm going for SQ, I don't give a damn about loudness. I downgraded from 2 l7s

1.01 cu ft $32
1.45 cu ft $30
1.3 mtx $40


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## 87regal (Apr 15, 2009)

Very important. Stick to the manufactures specs(unless you can use speaker modeling software). I would use AT LEAST minimum spec+polyfill.


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## BriIiance (Nov 16, 2011)

87regal said:


> Very important. Stick to the manufactures specs(unless you can use speaker modeling software). I would use AT LEAST minimum spec+polyfill.


I don't know what polyfill is but I'm just going to buy a box. if it says 1 cu ft that means its 1 cu ft, right? Not excluding this polyfill nonsense?


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## jcollin76 (Oct 26, 2010)

BriIiance said:


> I don't know what polyfill is but I'm just going to buy a box. if it says 1 cu ft that means its 1 cu ft, right? Not excluding this polyfill nonsense?


The box needs to be 1cu ft after your drivers displacement. And Poly fill is not nonsense, it acts as a way to make a smaller box seem larger to the drivers. A very useful tool in adjusting internal volume in enclosures.


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## KTMrida4life (Nov 24, 2011)

BriIiance said:


> I don't know what polyfill is but I'm just going to buy a box. if it says 1 cu ft that means its 1 cu ft, right? Not excluding this polyfill nonsense?


Polyfill is like the stuff inside your average pillow. When used correctly inside a sub enclosure it will make the subs *think* the box is bigger than it really is.


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## BriIiance (Nov 16, 2011)

so a .75cu ft box + poly fill could meet the minimum for my sub?


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## jcollin76 (Oct 26, 2010)

What happens inside the enclosure with poly fill is, as the air moves inside the box, It causes the fibers in the fill to vibrate rapidly. This creates heat inside the box, and effectively slows down the air movement. This creates the effect of a larger internal volume.


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## jcollin76 (Oct 26, 2010)

BriIiance said:


> so a .75cu ft box + poly fill could meet the minimum for my sub?


It would be close. You want the box as full as you can, but not compressed. Too much fill will not allow it to vibrate and slow the air movement. In other words it would eat up volume, and make it smaller.


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## jcollin76 (Oct 26, 2010)

General rule is 1lbs bag of fill per 1 cu ft of enclosure. So, about 3/4 bag of fill you can pick up at Walmart cheap.


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## BriIiance (Nov 16, 2011)

jcollin76 said:


> General rule is 1lbs bag of fill per 1 cu ft of enclosure. So, about 3/4 bag of fill you can pick up at Walmart cheap.


so would you recommend I get the .75 cu ft box and get 3/4 lbs of poly fill or get a 1cu ft box and get 1lb of poly fill?


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## KTMrida4life (Nov 24, 2011)

BriIiance said:


> so a .75cu ft box + poly fill could meet the minimum for my sub?


Mayyyyyyyybe. I doubt it. But you'll be closer.. probably more in the .9cu ft area. Not sure, Im not an expert.. I just put the stuff in my box to make me at the upper end of the recommend size box.


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## jcollin76 (Oct 26, 2010)

BriIiance said:


> so would you recommend I get the .75 cu ft box and get 3/4 lbs of poly fill or get a 1cu ft box and get 1lb of poly fill?


Well if you don't already have the box, I'd get the 1 cu ft. Then you wouldn't need the fill. You could use the fill as a tuning aid, and not to just get you to the minimum required air space. But putting the fill in might help your sub's lower response. Typically subs will perform better on the low side in larger enclosures.
Whereas with the .75, you'd need the fill just to Get you close.


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## BriIiance (Nov 16, 2011)

ok well I haven't got a box yet, and since the max is 1.5 I'll just get a 1cu ft box and get some poly fill?


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## quickaudi07 (May 19, 2010)

I'm not a expert, but if you get 1.5cu box, you will be set, unless you are limited to space in your car. I have used that Polly Fill as members are talking bout, and from experience, the sub gets overheated a lot faster. I had Jl Audio 10W7 sub, by using the the materiel to trick my sub and I have cooked the coil. 
You have to be very careful of how you use it and what you buy.
I would suggest to get a bigger box without the pillow inside of your box. 

I have learned my lesson, and now I bought a Morel Ult12", I build the box to specks and called it a day...

Now I don't have to worry about cu. or overheating issues, but that's just my suggestion to you, I may be wrong, members on here have more experience with that stuff. I'm just saying what i have learned from experience..


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## jcollin76 (Oct 26, 2010)

Sounds good. Don't worry about the poly, It's literally a couple bucks at Walmart. Try the box with out for a while, then try it with a lb. of fill in it and see what ya think. I'm betting you'll like it better in. That's always been my experience anyway.

Best of luck!


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## jcollin76 (Oct 26, 2010)

quickaudi07 said:


> I'm not a expert, but if you get 1.5cu box, you will be set, unless you are limited to space in your car. I have used that Polly Fill as they are talking bout, and from experience, the sub gets overheated a lot faster. I Jl Audio 10W7 sub, by using the the materiel to trick my sub. You have to be very careful of how you use it and what you buy.
> I would suggest to get a bigger box without the pillow inside of your box.
> 
> I have learned my lesson, and when i got my Morel Ult12" i build the box to specks and called it a day...


Did the pole vent get covered or something? What happened?


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## BriIiance (Nov 16, 2011)

changed initial post


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## Syaoran (Jun 27, 2011)

Get the 1.45 cu ft one.

If you're looking for SQ, most of the time subs will sound better on their larger recommended box. By doing this however, you'd need to lower power accordingly in an attempt to avoid over-excursion. 

As an example, Kicker lists all their subs with I think 3 box specs... one is the smallest one, which with the bigger power requirement will sound louder. The second one is a compromise, and the last one is for pure SQ and deep bass.

The box makes the sub sound nice, not the sub by itself. 

A cheap sub in the right box will sound better than an expensive sub in a wrong box, most of the time.

http://www.kicker.com/sites/default/files/2007CompVR.pdf

Look at the second page of the PDF, to the right, to see what I'm talking about.


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## jking29 (Jan 6, 2008)

Agreed.^^^


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## 2f150 (Oct 28, 2007)

Great discussion guys.


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## HondAudio (Oct 19, 2006)

BriIiance said:


> so a .75cu ft box + poly fill could meet the minimum for my sub?


No, it will not.


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## trumpet (Nov 14, 2010)

Out of the 3 boxes you listed I would get the one with the thickest MDF. For example, if one box is made of 5/8" MDF and another has 3/4" I would get the one with 3/4" MDF. The thicker wood helps reduce vibrations.


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## BuickGN (May 29, 2009)

Go with the 1.45 box. It will require less power for the same SPL and will most likely sound better and with more low end. My old 12W6s called for 1.25 and I ran them in 1.7 and eventually IB everytime I went with a larger box they sounded better.


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## fish (Jun 30, 2007)

BuickGN said:


> Go with the 1.45 box. It will require less power for the same SPL and will most likely sound better and with more low end. Everytime I went with a larger box they sounded better.


Yep, the larger box should more than likely help flatten out the sub's frequency response also.


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## mmiller (Mar 7, 2008)

BriIiance said:


> I don't know what polyfill is but I'm just going to buy a box. if it says 1 cu ft that means its 1 cu ft, right? Not excluding this polyfill nonsense?


If you don't know what polyfill is or does why comment????


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## mmiller (Mar 7, 2008)

quickaudi07 said:


> I'm not a expert, but if you get 1.5cu box, you will be set, unless you are limited to space in your car. I have used that Polly Fill as members are talking bout, and from experience, the sub gets overheated a lot faster. I had Jl Audio 10W7 sub, by using the the materiel to trick my sub and I have cooked the coil.
> You have to be very careful of how you use it and what you buy.
> I would suggest to get a bigger box without the pillow inside of your box.
> 
> ...


I would love to hear your explanation of how you blew a W7 because you used Polyfill in your enclosure...


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## BriIiance (Nov 16, 2011)

mmiller said:


> If you don't know what polyfill is or does why comment????


if you're not going to add anything helpful to the thread why comment?


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## mmiller (Mar 7, 2008)

BriIiance said:


> if you're not going to add anything helpful to the thread why comment?


Ok, use the search option on here, and you won't have to ask the same questions that have already been asked 500 times!

Is that Helpful enough for you???


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## Lorin (May 5, 2011)

if space used (in the car) isnt an issue, I would lean toward the larger box (1.45).


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## BriIiance (Nov 16, 2011)

Thanks for the help guys, I got the no name 1.45 cu ft box and I'm just gonna have a friend caulk it for me



mmiller said:


> Ok, use the search option on here, and you won't have to ask the same questions that have already been asked 500 times!
> 
> Is that Helpful enough for you???


after trying multiple search phrases (which there aren't many for this question) and getting nothing even relevent, on here and on google, I just decided to ask the question. if you are so privy to these prior threads, why didn't you just post a link to one instead of being completely unhelpful?


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## HondAudio (Oct 19, 2006)

Read this article:

Ultimate Polyfill Subwoofer Enclosure Resource - AudioJunkies

The charts aren't displaying, so see this link, as well:

http://www.moodym.com/audio/fiber.html


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## The Baron Groog (Mar 15, 2010)

The 1st chart is wrong! The last box says it's -ve14%, it's still actually 21% (give or take) gain. Otherwise useful resource


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