SPL/SQL Interchangable Ports?

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Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=75446
Printed Date: July 16, 2025 at 9:05 AM

Topic: SPL/SQL Interchangable Ports?

Posted By: alexv3305
Subject: SPL/SQL Interchangable Ports?
Date Posted: March 31, 2006 at 11:16 AM

Ok I figured out how to use WinISD, but someone double check my calculations. Would this work for two Kicker L5 15 inchers in a ported box?

Board thickness = 0.98 in or 1 in

Height = 18 in^3
Width = 41 in^3
Depth = 25.51 in^3
Total Volume = 8.536 ft^3

***Interchangable Ports***
SPL Port
~Tuning Freq = 45hz~
Port Dimensions = (16" x 5") Length = 4.54"
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SQL Port
~Tuning Freq = 30hz~
Port Dimensions = (16" x 5") Length = 19.83"

Just let me know if this would work...

Replies:

Posted By: stevdart
Date Posted: March 31, 2006 at 4:02 PM

Looks like you're on the right track with the tuning freqs you described (although I'm honestly not going to look up that woofer and work all this up!...I didn't even hear a "please"). Be sure you've allowed for the difference in the air volume between those two ports...or are these ports designed on the outside of the box? That might be the ticket for interchangeability.

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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: alexv3305
Date Posted: March 31, 2006 at 6:34 PM

the box is going to be designed to have interchangable ports so i can compete in spl and go for sql although kickers suck for sq. i jus want to know if it will work good.

......"please"......lol

thanks,

alex

Posted By: alexv3305
Date Posted: March 31, 2006 at 6:35 PM

stevdart wrote:

Be sure you've allowed for the difference in the air volume between those two ports...or are these ports designed on the outside of the box? That might be the ticket for interchangeability.

what do u mean allowed enough room for the difference in air volume between the two ports?

explain please...

Posted By: boardinbum
Date Posted: March 31, 2006 at 7:04 PM

The SPL port looks good. With your SQL port, I would almost tune it even a little lower.

Posted By: arrow12
Date Posted: March 31, 2006 at 7:46 PM

You are going to have to change the length of the ports. This takes up a different amount of volume in the box. I think this is what stevdart meant, but please correct me if I am wrong stevdart.

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That's my opinion. Take it, leave it, or correct me.

Posted By: stevdart
Date Posted: March 31, 2006 at 10:34 PM

You are right on, arrow12. A port structure 16 X 5 X 20 takes up much more displacement from an enclosure than 16 X 5 X 4.5. The box size remains the same but the airspace is different with the two port sizes, so that difference has to be accounted for when figuring tuning freq per air volume, which determines the port length. If the box were designed with a 4.5 inch port designed permanently inside, but with a configuration that allowed an add-on port structure to be mounted, you could make the switch easier. And most importantly, the airspace wouldn't diminish so greatly with the larger port structure inside.

Here's an idea of what I mean:

posted_image

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.