Sub Specs for Ported Box

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=32191
Printed Date: July 05, 2025 at 2:51 AM

Topic: Sub Specs for Ported Box

Posted By: silverbullet_00
Subject: Sub Specs for Ported Box
Date Posted: May 15, 2004 at 12:19 PM

I have never built a ported box before and plan on building one sometime with some 15" Audiobahn's. My question, with the following information, can someone help me as to what this all means? I need to know the information for the ports and the actual box size. I will be moulding this in my trunk with fiberglass. Any info is appreciated.

Thanks.

AW1508T
Ported Box
Air Space (Cu.) 3.55
Port Size (2)4x11.25
Port Vel. (%) 15.91
-3dB (Hz) 30
Tune Freq. (Hz) 35
Sub Disp. (Cu.) 0.47
Port Disp. (Cu.) 0.153
Total Volume (Cu.) 4
A port velocity of 5% or under is good SPL competition.
EPB 52

Replies:

Posted By: DYohn
Date Posted: May 15, 2004 at 1:43 PM

Start here: www.diysubwoofers.org.

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Posted By: italnpimp59
Date Posted: May 15, 2004 at 2:35 PM

go to JLaudio.com and click tutorials, then click ported boxes. it has the slot port formula there. its a hairy formula but it works!!!

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Posted By: stevdart
Date Posted: May 15, 2004 at 2:53 PM

Sub Disp. (Cu.) 0.47

How many subs is this??

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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: silverbullet_00
Date Posted: May 15, 2004 at 2:59 PM

stevdart wrote:

Sub Disp. (Cu.) 0.47
How many subs is this??

I got it from the Audiobahn site so I presume that is for 1 sub.

Posted By: stevdart
Date Posted: May 15, 2004 at 3:16 PM

Make sure you decide on the sub or subs you are going to use and get them ordered, then get the specific enclosure data before you construct the box. Ported box specs have to be exact. The sites that have been referenced above are great to begin with. Audiobahn also has help in the tech support section. Always go with the manufacturer's specifications for the sub you choose to use.

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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.