# SUB BOX TOO BIG?



## BIG! (May 28, 2009)

Hello All, just picked up a pair of alpine type E subs and didnt check the spec's. 
The new Type-E 12” specification requires 0.65 – 1.0 cubic feet air space, and the box has Volume (cu. ft.): 2.4 per chamber. the obvious solution is to get a box to match the subs, but i dont really want to do that. what if i used poly fill you think that may work?


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## spl152db (Dec 20, 2007)

polyfil isn't used like that. You can add sheets of wood or 2x4's. Or you can just use it and not worry as the .2 per sub most likely won't make that big of a difference.


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## rcurley55 (Jul 6, 2005)

2.4 per chamber means that your box is approximately 2x the size it needs to be. If you don't want a new box, fill the box with approximately 1 cubic foot of something that is rigid (wood, bricks, etc).

You may even have enough to port it.


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## BIG! (May 28, 2009)

thanks for the reply fellas, i will figure out a way to fill in the space to accommodate the subs, but what would be the consequence of just leaving it the way it is? does it loose sound quality?


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## lostnocturne (Dec 22, 2009)

Correct me if I'm wrong, but I think that you could blow a sub with using a box that's too big--especially by that much.

And you will definitely lose quality.


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## spl152db (Dec 20, 2007)

the problem with a box that large is that the air spring inside the box is too low for the sub. The sub is relying on that air spring to keep it under control at and below it's Fs. This sub has an Fs of 36hz which means below that frequency you will have a problem with the sub wanting to throw the cone out of the basket since it can't control it properly without the recommended enclosure. 

A box that has 2.4 cf PER woofer? Can you post some dimensions or a link to the box online? I highly doubt it's that big.


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## minbari (Mar 3, 2011)

add more subs!


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## malice (Aug 29, 2008)

spl152db said:


> the problem with a box that large is that the air spring inside the box is too low for the sub. The sub is relying on that air spring to keep it under control at and below it's Fs. This sub has an Fs of 36hz which means below that frequency you will have a problem with the sub wanting to throw the cone out of the basket since it can't control it properly without the recommended enclosure.
> 
> A box that has 2.4 cf PER woofer? Can you post some dimensions or a link to the box online? I highly doubt it's that big.


Yeah 4.8 cf total is freakin gigantic. I don't think that would fit in most cars.


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## minbari (Mar 3, 2011)

malice said:


> Yeah 4.8 cf total is freakin gigantic. I don't think that would fit in most cars.


I had 5 cuft in the back of my rx7. 

Sent from my Motorola Electrify using Tapatalk 2


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## [email protected] (Jun 12, 2008)

I dont see why you couldnt use it. Its gonna reduce the power handling and make it play lower. Other than that, do what others have suggested and start securing blocks of wood in there. You can use 2x4's so you can calculate how much space you are taking up.


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## BuickGN (May 29, 2009)

I would try it out as is first. Start off safe and follow infinite baffle rules and go from there. 

Every sub I've ever had has sounded better in a larger than recommended enclosure. I've run several small box subs infinite baffle with excellent results. Look around the board, people have used common "box" subs like the W6, W7, Ultimo, and many others IB ( which is like a huge sealed box) with great results.

Try em out and keep an eye on excursion. You won't hurt them as long as you pay attention. Run a subsonic filter if your amp or processor has one. You will probably like the sound more than the manufacturer's spec box. Power handling goes down but that's not the whole story. It hits full excursion at a lower power level so power handling is reduced but that's because it hits full output at a lower power level. In other words, you're not losing any output with a properly setup subsonic filter and you're gaining efficiency. No air spring needed lol.


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## BIG! (May 28, 2009)

here's the box im talking about, its the last one on the list. and also i was thinking of using Styrofoam blocks instead of wood how bout that?

Reference Series – HSR - Bassworx

and these are the subs.

Alpine Electronics of America, Inc.


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## spl152db (Dec 20, 2007)

Yea thats total volume not per speaker. You'll be fine. Run them, have fun. 

Sent from my ADR6400L using Tapatalk


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## BuickGN (May 29, 2009)

Again, I would run them as is and see how you like them in the large box first. You've lost the trunk space already so you might as well try them with the full volume available before you begin decreasing volume. You will probably like them in the large volume.


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## BIG! (May 28, 2009)

BuickGN said:


> Again, I would run them as is and see how you like them in the large box first. You've lost the trunk space already so you might as well try them with the full volume available before you begin decreasing volume. You will probably like them in the large volume.


yeah man, think ill do just that. thank you.


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## BuickGN (May 29, 2009)

BIG! said:


> yeah man, think ill do just that. thank you.


Looking at the actual box, I think it's the perfect size for those subs since it looks like it's listed as total volume and not volume per sub as spl152db suggested. Either way you should be fine. Let us know how it turns out.


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## diatribe (Aug 11, 2008)

Yea, that box is 2.4 total air space. Divide that by 2 drivers and you are looking at 1.2 per sub. Subtract 0.12 for woofer displacement and you're looking at 1.08 per sub.

That's on the upper end for those subs so you should be fine. It should sound fine, bu you will not have as much power handling capability as a smaller box.


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## mos805 (Nov 30, 2011)

diatribe said:


> but you will not have as much power handling capability as a smaller box.


This confused me so much when I knew little about car audio because I always thought it meant my sub wouldn't play as loud and was a negative thing (when I thought that more watts= more boom). So I will just say that it will take less power to get to the subs full excursion, with the bigger box it will take less power but it will also take less power to get the full output.


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## spl152db (Dec 20, 2007)

it will take less power at lower frequencies to reach max xmax aka max volume. You will NOT notice a difference in total output with this box. Please just use it and enjoy. This topic was done 5 posts ago when I told you it was fine. Your loss in power handling is maybe at most 10-20 watts. You won't notice this.


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## BuickGN (May 29, 2009)

mos805 said:


> This confused me so much when I knew little about car audio because I always thought it meant my sub wouldn't play as loud and was a negative thing (when I thought that more watts= more boom). So I will just say that it will take less power to get to the subs full excursion, with the bigger box it will take less power but it will also take less power to get the full output.


Exactly. You lose power handling but gain efficiency and you end up with the same output but with less power required... as long as you run a subsonic filter.


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## BIG! (May 28, 2009)

spl152db said:


> Please just use it and enjoy. This topic was done 5 posts ago when I told you it was fine. Your loss in power handling is maybe at most 10-20 watts. You won't notice this.


i got it the first time  . thanks to you and mr. buick. and since we're at it just want to let you guyz know that i just recieved the subs but im still wating on my jvc kwav70bt so i can hook it all up and give ya'll an update.


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