two ports into one
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=99886
Printed Date: May 16, 2025 at 6:32 PM
Topic: two ports into one
Posted By: killa101
Subject: two ports into one
Date Posted: December 11, 2007 at 2:35 PM
How would I turn this enclosure into one with a single port in the center of the enclosure?
Link Here
Replies:
Posted By: haemphyst
Date Posted: December 11, 2007 at 3:16 PM
You'll probably run out of box volume before you get enough line. Why not just build it per the plans?
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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: killa101
Date Posted: December 11, 2007 at 3:22 PM
I don't really want to do it i just want to know how to mathmatically.
Posted By: i am an idiot
Date Posted: December 11, 2007 at 4:28 PM
This would be 2 ports but they are in the middle 
Posted By: DYohn
Date Posted: December 11, 2007 at 4:44 PM
killa101 wrote:
How would I turn this enclosure into one with a single port in the center of the enclosure?
You couldn't. But you could certainly design a dual-driver single ported enclosure using those speakers. ------------- Support the12volt.com
Posted By: killa101
Date Posted: December 11, 2007 at 5:15 PM
I guess what I really need to know is when i designed an enclosure in WinISD I got the best results for an enclosure that is 3 cubic foot big and 32 Hz for a tuning frequency. If I wanted to put a port in the middle how would I go about doing that? I know how to do it around the sides but I wanted to know how to put it in the middle?
Posted By: killa101
Date Posted: December 11, 2007 at 7:32 PM
What i'm looking for is something that looks like this. How would the port length work and how wide is the port going to be when it hits the back wall?
Posted By: jmelton86
Date Posted: December 11, 2007 at 7:39 PM
DYohn] wrote:
QUOTE=killa101]How would I turn this enclosure into one with a single port in the center of the enclosure?
You couldn't. But you could certainly design a dual-driver single ported enclosure using those speakers.[/QUOTE] That's what your latest pic is, a dual-driver single ported enclosure. Usually it's best to have each sub in thier own enclosure, like first pic you showed. The reason is because if one driver was to fail, the other wouldn't be affected by all the extra airspace (for both of them). ------------- 2013 Kia Rio -90a alternator
DDX470HD GTO14001 GTO1014D (x3)
Big3 in 1/0G
1/0G to GTO14001
Posted By: stevdart
Date Posted: December 11, 2007 at 7:44 PM
killa101 wrote:
I guess what I really need to know is when i designed an enclosure in WinISD I got the best results for an enclosure that is 3 cubic foot big and 32 Hz for a tuning frequency. If I wanted to put a port in the middle how would I go about doing that? I know how to do it around the sides but I wanted to know how to put it in the middle?
You would first have to answer this: How long must the port be while keeping port noise in check? And, is this length a few inches less than the inside depth of the box? If yes, you would fit two baffles at the center of the box that extend from top to bottom. The distance between the baffles is slot opening width, just the same as if you put the port along the side of the box. You would need a few inches of free space at the end of the port. The box is a single chamber, not divided. But if the port must be longer than the box can be deep, you can't do it in the center with one single port. You would instead use a dual chamber box with dual ports as I am an idiot illustrated, or put the port off to one side. I don't accept your last illustration as a proper vented enclosure. It's a muddy mix between a single chamber and dual chamber and I wouldn't count on the port response accuracy. My opinion is that a multi-driver single chamber enclosure must share airspace other than that which is comprised of port airspace. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: i am an idiot
Date Posted: December 11, 2007 at 8:06 PM
How about adding one more piece of wood and have it look like this. 
Posted By: jmelton86
Date Posted: December 11, 2007 at 8:12 PM
killa101, what exactly are you trying to do here?
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2013 Kia Rio -90a alternator
DDX470HD GTO14001 GTO1014D (x3)
Big3 in 1/0G
1/0G to GTO14001
Posted By: killa101
Date Posted: December 11, 2007 at 10:36 PM
stevdart wrote:
I don't accept your last illustration as a proper vented enclosure. It's a muddy mix between a single chamber and dual chamber and I wouldn't count on the port response accuracy. My opinion is that a multi-driver single chamber enclosure must share airspace other than that which is comprised of port airspace.
That is what I was looking for. I was looking to put the port in the middle but I guess i might just put it in the side like the picture below.
I would just have two seperate chambers but I'm getting some really long port lengths and I don't think i will be able to get it to work that way. Right now I'm getting like 50 inches for both of the ports. I don't like the idea of a single chamber but if that is what I have to do then that's ok.
Posted By: DYohn
Date Posted: December 12, 2007 at 1:08 PM
Why use a slot port? if you want your port(s) between the drivers, use round ports. ------------- Support the12volt.com
Posted By: haemphyst
Date Posted: December 12, 2007 at 1:11 PM
Like I said:
haemphyst wrote:
You'll probably run out of box volume before you get enough line. Why not just build it per the plans?
------------- It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."
Posted By: DYohn
Date Posted: December 12, 2007 at 1:19 PM
If you must use a slot port and want it in the center, and it needs to be longer than the depth of the enclosure, you could design something like this: 
And actually the segment in the middle can be a single wall... ------------- Support the12volt.com
Posted By: stevdart
Date Posted: December 12, 2007 at 5:52 PM
Round ports, of course! I guess I wasn't thinking outside of the box like DYohn is.  ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: killa101
Date Posted: December 12, 2007 at 9:24 PM
I convinced myself i like my idea of putting the port on the side.
I would use the round ports but they still had to be bent because they were too long. Plus i have plenty of wood and nothing for round ports.
Thanks for your help guys. 
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