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Discussion Starter #1 (Edited)
I bought a SWR-843D to replace my factory sub in the rear deck of my charger. I mounted the sub and put a sealed box around .47 ft^3 around it, it sounds ok. Was thinking of going to a ported box, this is where I'm clueless. What we did was cut a hole in on my back carpet that goes over the deck so that you can see the sub from inside the car, this looks pretty cool, so with that said I have a hole in my rear deck carpet. I'm thinking a few designs for a ported box

1)a column type setup where it goes from the trunks bottom to the deck, having a rounded port that goes right underneath the hole that is cut in the deck

2)making a speaker box on the bottom of the trunk, extended the port from the box upward through the hole

difference being the first would be build upright and the second being built flat with the port extending.

With this I have a few questions, can the port be inside the box / outside the box / either one / both (meaning half inside the box and half outside). According to the specs the box needs to be .25-.60 volume box range and .70 gross internal volume. With these measurements how do I figue out the dimensions of the box as well as the port. There is a square port and a round port, do both boxes need the piece inside the box? If so how big does this need to be? As far as the freq I just want bass really, I guess around 35. I can pretty much build anything but it's the measurements on this that is driving me nuts.

Any help on this would be great, thanks.


**Edit**
Looking at the documentation it says
optimum Vented Box
Gross Internal Volume .70ft
Fb 36hz

So can I just use any box calculator and get .70ft and use the link below to get the port diameter and length? In doing so I get Diameter 4 and length 34.4 inches.
http://www.mobileinformationlabs.com/HowTo-1Woofer-Box-CAL Port lenth 1.htm

Thanks once again
 

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I use to have a swr-843d but I gave it to a friend since I don't have any use for it now (I have a 15"). This sub does very well in a .25 cub ft sealed enclosure and good in a .4 or larger ported box.

If you read the alpine swr-843d/823d thread on this forum Jim Walter, an Alpine Engineer, said it can perform well in infinite baffle and he said it is possible to power only one of the voice coils in order to make the parameters more suitable for IB usage, the only draw back is that is will reduce the power handling of the sub since you will be only using one voice coil. I would message him and try to talk to him about this in more detail since he would be the best person to talk to about the sub.

http://www.diymobileaudio.com/forum/member-reviews-product-comparisons/106292-alpine-swr-823d-game-over.html
x2....good advice

width x height x depth then divide by 1728 = total cubic feet

The port can be in or out of the box, you just need to account for the port displacement accordingly
 

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Discussion Starter #3
Thanks, I didn't want to bother that guy b/c my question is more on the box building itself, not the sub. Guess my main question now is the edit I made the first post the correct way to go about it?

Thanks
 

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build the box to .70 then plug in the info for the port size and length..... it's ok to use a chimney style port to reach the old opening....if you go with round port use a 3" minimum diameter...play with the numbers until you get a port size to fit your box and install
 

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Discussion Starter #5 (Edited)
build the box to .70 then plug in the info for the port size and length..... it's ok to use a chimney style port to reach the old opening....if you go with round port use a 3" minimum diameter...play with the numbers until you get a port size to fit your box and install
Thanks, dude wanted 150 to build this. Pretty sure I can knock it out in a day for 50.

In the first response you state it can be in or out, but can it be both in the box and out of the box? Also does anyone know any nice ways to mask the port so theres not a white tube sticking out?


Playing with the measurements how does a bigger port diameter make it to where you have to have a longer port? Thought it should be other way around.

I'm full of questions. I'm looking in to doing a vented box, this way I can have the sub at the top of the box showing through the factory spot and the vent on the bottom. I'm pretty confused on the slot port vent length, say I build a box that is 13x10x13 looking at the calculator the port width would be 13 the port height 2.75<-? box volume .65 Fb 36 I get the port length of 99 inches. So my question, does this make any type of sense, do I have something completely wrong. Also this is suppose to make a L shape in the box, how close to the box frame do I get with this. Thanks
 
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