fiberglass volume calculating

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=109123
Printed Date: July 05, 2025 at 3:23 AM

Topic: fiberglass volume calculating

Posted By: dak446
Subject: fiberglass volume calculating
Date Posted: November 21, 2008 at 4:52 PM

I have never actually built a custom fiberglass enclosure, but when i get my new yukon im going to make it all one nice enclosure for all my subs and everything. but my question is how do you calculate how much volume is in you enclosure, after displacement of subs, and how to find out how to size your port to tune it properly. thanks

Replies:

Posted By: i am an idiot
Date Posted: November 21, 2008 at 6:01 PM

No idea how to figure volume before you build the box, but this works if you have the enclosure. Build the enclosure and cut the woofer hole out. Purchase a bean bag chair and cut it open to get to the pellets inside. Fill your enclosure with the pellets. Then dump the pellets into a box that you built with an inside dimension of 12" x 12" x however many feet you think you need it. Measure to see how deep the pellets are. 12 x 12 x height of pellets in inches, = cubic inches. Divide that by 1728 = Cubic Feet.

Posted By: dak446
Date Posted: November 24, 2008 at 7:44 PM

well that's actually a really good idea. i had never thought of doing that. i suppose i could build it to be "asthetically pleasing" and all that, and then fill it full of something like those beans and calculate the volume, and subtract the displacement of the subs, and then build the port to match the volume? do you think that would work or what?

Posted By: i am an idiot
Date Posted: November 24, 2008 at 8:21 PM

Yes I think that would work.