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Calculating port length

Printed From: the12volt.com
Forum Name: Fiberglass, Fabrication, and Interiors
Forum Discription: Fiberglass Kick Panels, Subwoofer Enclosures, Plexiglas, Fabrics, Materials, Finishes, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=84980
Printed Date: May 03, 2024 at 4:34 PM


Topic: Calculating port length

Posted By: punkbastard
Subject: Calculating port length
Date Posted: November 01, 2006 at 10:01 PM

So, I've never really been a big fan of ported boxes, mostly because I was always worried that if I didn't nail the specs to the T then it would sound terrible and blow the sub.  However, I am redoing my company's demo car and the main consensus is go ported for the 3 Rockford T1s that I'm puttin in there.

I have seen pictures of enclosures made for multiple subs that have just one large port.  This just can't be right.  It just doesn't seem like you could get each sub to perform the same when they are sharing one big port.  The other thing is that these boxes are typically partially fiberglass so the exact volume going into it is not known, can this blow a sub?  From what I understand, port volume and enclosure volume directly affect the tuning frequency of the box, which if unmatched with the manufacturers specs, can damage the sub.

Can somebody please help me figure out how I can build one slot load box with a common chamber for 3 subs?  Or should I just do 3 seperate boxes with 3 seperate ports? 




Replies:

Posted By: sean 371
Date Posted: November 05, 2006 at 7:08 PM
There is a fair amount of room for error as far as volume goes. The volume/diameter of the port affects the frequency. I've tried winisd to calculate all that, but I don't trust that I'm putting in all the values properly and all that. All the ported boxes I've built, I've gone off of the manufacturer's specs, and they've sounded real good. And I would do a separate chamber for each sub. If nothing else, in case one sub blows, you can still use the other two without worrying about all that extra volume.





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